index.html

<!doctype html>
<html>
<head>
<meta charset='UTF-8'><meta name='viewport' content='width=device-width initial-scale=1'>
<title>JS-Toolbox</title><style type='text/css'>html {overflow-x: initial !important;}:root { --bg-color:#ffffff; --text-color:#333333; --select-text-bg-color:#B5D6FC; --select-text-font-color:auto; --monospace:"Lucida Console",Consolas,"Courier",monospace; }
html { font-size: 14px; background-color: var(--bg-color); color: var(--text-color); font-family: "Helvetica Neue", Helvetica, Arial, sans-serif; -webkit-font-smoothing: antialiased; }
body { margin: 0px; padding: 0px; height: auto; bottom: 0px; top: 0px; left: 0px; right: 0px; font-size: 1rem; line-height: 1.42857; overflow-x: hidden; background: inherit; tab-size: 4; }
iframe { margin: auto; }
a.url { word-break: break-all; }
a:active, a:hover { outline: 0px; }
.in-text-selection, ::selection { text-shadow: none; background: var(--select-text-bg-color); color: var(--select-text-font-color); }
#write { margin: 0px auto; height: auto; width: inherit; word-break: normal; overflow-wrap: break-word; position: relative; white-space: normal; overflow-x: visible; padding-top: 40px; }
#write.first-line-indent p { text-indent: 2em; }
#write.first-line-indent li p, #write.first-line-indent p * { text-indent: 0px; }
#write.first-line-indent li { margin-left: 2em; }
.for-image #write { padding-left: 8px; padding-right: 8px; }
body.typora-export { padding-left: 30px; padding-right: 30px; }
.typora-export .footnote-line, .typora-export li, .typora-export p { white-space: pre-wrap; }
@media screen and (max-width: 500px) {
  body.typora-export { padding-left: 0px; padding-right: 0px; }
  #write { padding-left: 20px; padding-right: 20px; }
  .CodeMirror-sizer { margin-left: 0px !important; }
  .CodeMirror-gutters { display: none !important; }
}
#write li > figure:last-child { margin-bottom: 0.5rem; }
#write ol, #write ul { position: relative; }
img { max-width: 100%; vertical-align: middle; }
button, input, select, textarea { color: inherit; font: inherit; }
input[type="checkbox"], input[type="radio"] { line-height: normal; padding: 0px; }
*, ::after, ::before { box-sizing: border-box; }
#write h1, #write h2, #write h3, #write h4, #write h5, #write h6, #write p, #write pre { width: inherit; }
#write h1, #write h2, #write h3, #write h4, #write h5, #write h6, #write p { position: relative; }
p { line-height: inherit; }
h1, h2, h3, h4, h5, h6 { break-after: avoid-page; break-inside: avoid; orphans: 4; }
p { orphans: 4; }
h1 { font-size: 2rem; }
h2 { font-size: 1.8rem; }
h3 { font-size: 1.6rem; }
h4 { font-size: 1.4rem; }
h5 { font-size: 1.2rem; }
h6 { font-size: 1rem; }
.md-math-block, .md-rawblock, h1, h2, h3, h4, h5, h6, p { margin-top: 1rem; margin-bottom: 1rem; }
.hidden { display: none; }
.md-blockmeta { color: rgb(204, 204, 204); font-weight: 700; font-style: italic; }
a { cursor: pointer; }
sup.md-footnote { padding: 2px 4px; background-color: rgba(238, 238, 238, 0.7); color: rgb(85, 85, 85); border-radius: 4px; cursor: pointer; }
sup.md-footnote a, sup.md-footnote a:hover { color: inherit; text-transform: inherit; text-decoration: inherit; }
#write input[type="checkbox"] { cursor: pointer; width: inherit; height: inherit; }
figure { overflow-x: auto; margin: 1.2em 0px; max-width: calc(100% + 16px); padding: 0px; }
figure > table { margin: 0px !important; }
tr { break-inside: avoid; break-after: auto; }
thead { display: table-header-group; }
table { border-collapse: collapse; border-spacing: 0px; width: 100%; overflow: auto; break-inside: auto; text-align: left; }
table.md-table td { min-width: 32px; }
.CodeMirror-gutters { border-right: 0px; background-color: inherit; }
.CodeMirror-linenumber { user-select: none; }
.CodeMirror { text-align: left; }
.CodeMirror-placeholder { opacity: 0.3; }
.CodeMirror pre { padding: 0px 4px; }
.CodeMirror-lines { padding: 0px; }
div.hr:focus { cursor: none; }
#write pre { white-space: pre-wrap; }
#write.fences-no-line-wrapping pre { white-space: pre; }
#write pre.ty-contain-cm { white-space: normal; }
.CodeMirror-gutters { margin-right: 4px; }
.md-fences { font-size: 0.9rem; display: block; break-inside: avoid; text-align: left; overflow: visible; white-space: pre; background: inherit; position: relative !important; }
.md-diagram-panel { width: 100%; margin-top: 10px; text-align: center; padding-top: 0px; padding-bottom: 8px; overflow-x: auto; }
#write .md-fences.mock-cm { white-space: pre-wrap; }
.md-fences.md-fences-with-lineno { padding-left: 0px; }
#write.fences-no-line-wrapping .md-fences.mock-cm { white-space: pre; overflow-x: auto; }
.md-fences.mock-cm.md-fences-with-lineno { padding-left: 8px; }
.CodeMirror-line, twitterwidget { break-inside: avoid; }
.footnotes { opacity: 0.8; font-size: 0.9rem; margin-top: 1em; margin-bottom: 1em; }
.footnotes + .footnotes { margin-top: 0px; }
.md-reset { margin: 0px; padding: 0px; border: 0px; outline: 0px; vertical-align: top; background: 0px 0px; text-decoration: none; text-shadow: none; float: none; position: static; width: auto; height: auto; white-space: nowrap; cursor: inherit; -webkit-tap-highlight-color: transparent; line-height: normal; font-weight: 400; text-align: left; box-sizing: content-box; direction: ltr; }
li div { padding-top: 0px; }
blockquote { margin: 1rem 0px; }
li .mathjax-block, li p { margin: 0.5rem 0px; }
li { margin: 0px; position: relative; }
blockquote > :last-child { margin-bottom: 0px; }
blockquote > :first-child, li > :first-child { margin-top: 0px; }
.footnotes-area { color: rgb(136, 136, 136); margin-top: 0.714rem; padding-bottom: 0.143rem; white-space: normal; }
#write .footnote-line { white-space: pre-wrap; }
@media print {
  body, html { border: 1px solid transparent; height: 99%; break-after: avoid; break-before: avoid; font-variant-ligatures: no-common-ligatures; }
  #write { margin-top: 0px; padding-top: 0px; border-color: transparent !important; }
  .typora-export * { -webkit-print-color-adjust: exact; }
  html.blink-to-pdf { font-size: 13px; }
  .typora-export #write { padding-left: 32px; padding-right: 32px; padding-bottom: 0px; break-after: avoid; }
  .typora-export #write::after { height: 0px; }
}
.footnote-line { margin-top: 0.714em; font-size: 0.7em; }
a img, img a { cursor: pointer; }
pre.md-meta-block { font-size: 0.8rem; min-height: 0.8rem; white-space: pre-wrap; background: rgb(204, 204, 204); display: block; overflow-x: hidden; }
p > .md-image:only-child:not(.md-img-error) img, p > img:only-child { display: block; margin: auto; }
#write.first-line-indent p > .md-image:only-child:not(.md-img-error) img { left: -2em; position: relative; }
p > .md-image:only-child { display: inline-block; width: 100%; }
#write .MathJax_Display { margin: 0.8em 0px 0px; }
.md-math-block { width: 100%; }
.md-math-block:not(:empty)::after { display: none; }
[contenteditable="true"]:active, [contenteditable="true"]:focus, [contenteditable="false"]:active, [contenteditable="false"]:focus { outline: 0px; box-shadow: none; }
.md-task-list-item { position: relative; list-style-type: none; }
.task-list-item.md-task-list-item { padding-left: 0px; }
.md-task-list-item > input { position: absolute; top: 0px; left: 0px; margin-left: -1.2em; margin-top: calc(1em - 10px); border: none; }
.math { font-size: 1rem; }
.md-toc { min-height: 3.58rem; position: relative; font-size: 0.9rem; border-radius: 10px; }
.md-toc-content { position: relative; margin-left: 0px; }
.md-toc-content::after, .md-toc::after { display: none; }
.md-toc-item { display: block; color: rgb(65, 131, 196); }
.md-toc-item a { text-decoration: none; }
.md-toc-inner:hover { text-decoration: underline; }
.md-toc-inner { display: inline-block; cursor: pointer; }
.md-toc-h1 .md-toc-inner { margin-left: 0px; font-weight: 700; }
.md-toc-h2 .md-toc-inner { margin-left: 2em; }
.md-toc-h3 .md-toc-inner { margin-left: 4em; }
.md-toc-h4 .md-toc-inner { margin-left: 6em; }
.md-toc-h5 .md-toc-inner { margin-left: 8em; }
.md-toc-h6 .md-toc-inner { margin-left: 10em; }
@media screen and (max-width: 48em) {
  .md-toc-h3 .md-toc-inner { margin-left: 3.5em; }
  .md-toc-h4 .md-toc-inner { margin-left: 5em; }
  .md-toc-h5 .md-toc-inner { margin-left: 6.5em; }
  .md-toc-h6 .md-toc-inner { margin-left: 8em; }
}
a.md-toc-inner { font-size: inherit; font-style: inherit; font-weight: inherit; line-height: inherit; }
.footnote-line a:not(.reversefootnote) { color: inherit; }
.md-attr { display: none; }
.md-fn-count::after { content: "."; }
code, pre, samp, tt { font-family: var(--monospace); }
kbd { margin: 0px 0.1em; padding: 0.1em 0.6em; font-size: 0.8em; color: rgb(36, 39, 41); background: rgb(255, 255, 255); border: 1px solid rgb(173, 179, 185); border-radius: 3px; box-shadow: rgba(12, 13, 14, 0.2) 0px 1px 0px, rgb(255, 255, 255) 0px 0px 0px 2px inset; white-space: nowrap; vertical-align: middle; }
.md-comment { color: rgb(162, 127, 3); opacity: 0.8; font-family: var(--monospace); }
code { text-align: left; vertical-align: initial; }
a.md-print-anchor { white-space: pre !important; border-width: initial !important; border-style: none !important; border-color: initial !important; display: inline-block !important; position: absolute !important; width: 1px !important; right: 0px !important; outline: 0px !important; background: 0px 0px !important; text-decoration: initial !important; text-shadow: initial !important; }
.md-inline-math .MathJax_SVG .noError { display: none !important; }
.html-for-mac .inline-math-svg .MathJax_SVG { vertical-align: 0.2px; }
.md-math-block .MathJax_SVG_Display { text-align: center; margin: 0px; position: relative; text-indent: 0px; max-width: none; max-height: none; min-height: 0px; min-width: 100%; width: auto; overflow-y: hidden; display: block !important; }
.MathJax_SVG_Display, .md-inline-math .MathJax_SVG_Display { width: auto; margin: inherit; display: inline-block !important; }
.MathJax_SVG .MJX-monospace { font-family: var(--monospace); }
.MathJax_SVG .MJX-sans-serif { font-family: sans-serif; }
.MathJax_SVG { display: inline; font-style: normal; font-weight: 400; line-height: normal; zoom: 90%; text-indent: 0px; text-align: left; text-transform: none; letter-spacing: normal; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; }
.MathJax_SVG * { transition: none 0s ease 0s; }
.MathJax_SVG_Display svg { vertical-align: middle !important; margin-bottom: 0px !important; margin-top: 0px !important; }
.os-windows.monocolor-emoji .md-emoji { font-family: "Segoe UI Symbol", sans-serif; }
.md-diagram-panel > svg { max-width: 100%; }
[lang="flow"] svg, [lang="mermaid"] svg { max-width: 100%; height: auto; }
[lang="mermaid"] .node text { font-size: 1rem; }
table tr th { border-bottom: 0px; }
video { max-width: 100%; display: block; margin: 0px auto; }
iframe { max-width: 100%; width: 100%; border: none; }
.highlight td, .highlight tr { border: 0px; }
svg[id^="mermaidChart"] { line-height: 1em; }
mark { background: rgb(255, 255, 0); color: rgb(0, 0, 0); }
.md-html-inline .md-plain, .md-html-inline strong, mark .md-inline-math, mark strong { color: inherit; }
mark .md-meta { color: rgb(0, 0, 0); opacity: 0.3 !important; }


.CodeMirror { height: auto; }
.CodeMirror.cm-s-inner { background: inherit; }
.CodeMirror-scroll { overflow: auto hidden; z-index: 3; }
.CodeMirror-gutter-filler, .CodeMirror-scrollbar-filler { background-color: rgb(255, 255, 255); }
.CodeMirror-gutters { border-right: 1px solid rgb(221, 221, 221); background: inherit; white-space: nowrap; }
.CodeMirror-linenumber { padding: 0px 3px 0px 5px; text-align: right; color: rgb(153, 153, 153); }
.cm-s-inner .cm-keyword { color: rgb(119, 0, 136); }
.cm-s-inner .cm-atom, .cm-s-inner.cm-atom { color: rgb(34, 17, 153); }
.cm-s-inner .cm-number { color: rgb(17, 102, 68); }
.cm-s-inner .cm-def { color: rgb(0, 0, 255); }
.cm-s-inner .cm-variable { color: rgb(0, 0, 0); }
.cm-s-inner .cm-variable-2 { color: rgb(0, 85, 170); }
.cm-s-inner .cm-variable-3 { color: rgb(0, 136, 85); }
.cm-s-inner .cm-string { color: rgb(170, 17, 17); }
.cm-s-inner .cm-property { color: rgb(0, 0, 0); }
.cm-s-inner .cm-operator { color: rgb(152, 26, 26); }
.cm-s-inner .cm-comment, .cm-s-inner.cm-comment { color: rgb(170, 85, 0); }
.cm-s-inner .cm-string-2 { color: rgb(255, 85, 0); }
.cm-s-inner .cm-meta { color: rgb(85, 85, 85); }
.cm-s-inner .cm-qualifier { color: rgb(85, 85, 85); }
.cm-s-inner .cm-builtin { color: rgb(51, 0, 170); }
.cm-s-inner .cm-bracket { color: rgb(153, 153, 119); }
.cm-s-inner .cm-tag { color: rgb(17, 119, 0); }
.cm-s-inner .cm-attribute { color: rgb(0, 0, 204); }
.cm-s-inner .cm-header, .cm-s-inner.cm-header { color: rgb(0, 0, 255); }
.cm-s-inner .cm-quote, .cm-s-inner.cm-quote { color: rgb(0, 153, 0); }
.cm-s-inner .cm-hr, .cm-s-inner.cm-hr { color: rgb(153, 153, 153); }
.cm-s-inner .cm-link, .cm-s-inner.cm-link { color: rgb(0, 0, 204); }
.cm-negative { color: rgb(221, 68, 68); }
.cm-positive { color: rgb(34, 153, 34); }
.cm-header, .cm-strong { font-weight: 700; }
.cm-del { text-decoration: line-through; }
.cm-em { font-style: italic; }
.cm-link { text-decoration: underline; }
.cm-error { color: red; }
.cm-invalidchar { color: red; }
.cm-constant { color: rgb(38, 139, 210); }
.cm-defined { color: rgb(181, 137, 0); }
div.CodeMirror span.CodeMirror-matchingbracket { color: rgb(0, 255, 0); }
div.CodeMirror span.CodeMirror-nonmatchingbracket { color: rgb(255, 34, 34); }
.cm-s-inner .CodeMirror-activeline-background { background: inherit; }
.CodeMirror { position: relative; overflow: hidden; }
.CodeMirror-scroll { height: 100%; outline: 0px; position: relative; box-sizing: content-box; background: inherit; }
.CodeMirror-sizer { position: relative; }
.CodeMirror-gutter-filler, .CodeMirror-hscrollbar, .CodeMirror-scrollbar-filler, .CodeMirror-vscrollbar { position: absolute; z-index: 6; display: none; }
.CodeMirror-vscrollbar { right: 0px; top: 0px; overflow: hidden; }
.CodeMirror-hscrollbar { bottom: 0px; left: 0px; overflow: hidden; }
.CodeMirror-scrollbar-filler { right: 0px; bottom: 0px; }
.CodeMirror-gutter-filler { left: 0px; bottom: 0px; }
.CodeMirror-gutters { position: absolute; left: 0px; top: 0px; padding-bottom: 30px; z-index: 3; }
.CodeMirror-gutter { white-space: normal; height: 100%; box-sizing: content-box; padding-bottom: 30px; margin-bottom: -32px; display: inline-block; }
.CodeMirror-gutter-wrapper { position: absolute; z-index: 4; background: 0px 0px !important; border: none !important; }
.CodeMirror-gutter-background { position: absolute; top: 0px; bottom: 0px; z-index: 4; }
.CodeMirror-gutter-elt { position: absolute; cursor: default; z-index: 4; }
.CodeMirror-lines { cursor: text; }
.CodeMirror pre { border-radius: 0px; border-width: 0px; background: 0px 0px; font-family: inherit; font-size: inherit; margin: 0px; white-space: pre; overflow-wrap: normal; color: inherit; z-index: 2; position: relative; overflow: visible; }
.CodeMirror-wrap pre { overflow-wrap: break-word; white-space: pre-wrap; word-break: normal; }
.CodeMirror-code pre { border-right: 30px solid transparent; width: fit-content; }
.CodeMirror-wrap .CodeMirror-code pre { border-right: none; width: auto; }
.CodeMirror-linebackground { position: absolute; left: 0px; right: 0px; top: 0px; bottom: 0px; z-index: 0; }
.CodeMirror-linewidget { position: relative; z-index: 2; overflow: auto; }
.CodeMirror-wrap .CodeMirror-scroll { overflow-x: hidden; }
.CodeMirror-measure { position: absolute; width: 100%; height: 0px; overflow: hidden; visibility: hidden; }
.CodeMirror-measure pre { position: static; }
.CodeMirror div.CodeMirror-cursor { position: absolute; visibility: hidden; border-right: none; width: 0px; }
.CodeMirror div.CodeMirror-cursor { visibility: hidden; }
.CodeMirror-focused div.CodeMirror-cursor { visibility: inherit; }
.cm-searching { background: rgba(255, 255, 0, 0.4); }
@media print {
  .CodeMirror div.CodeMirror-cursor { visibility: hidden; }
}


/* Flowchart variables */
/* Sequence Diagram variables */
/* Gantt chart variables */
/* state colors */
.label {
  
  color: #333; }

.label text {
  fill: #333; }

.node rect,
.node circle,
.node ellipse,
.node polygon {
  fill: #BDD5EA;
  stroke: #9370DB;
  stroke-width: 1px; }

.node .label {
  text-align: center; }

.node.clickable {
  cursor: pointer; }

.arrowheadPath {
  fill: lightgrey; }

.edgePath .path {
  stroke: lightgrey;
  stroke-width: 1.5px; }

.edgeLabel {
  background-color: #e8e8e8;
  text-align: center; }

.cluster rect {
  fill: #6D6D65;
  stroke: rgba(255, 255, 255, 0.25);
  stroke-width: 1px; }

.cluster text {
  fill: #F9FFFE; }

div.mermaidTooltip {
  position: absolute;
  text-align: center;
  max-width: 200px;
  padding: 2px;
  
  font-size: 12px;
  background: #6D6D65;
  border: 1px solid rgba(255, 255, 255, 0.25);
  border-radius: 2px;
  pointer-events: none;
  z-index: 100; }

.actor {
  stroke: #81B1DB;
  fill: #BDD5EA; }

text.actor {
  fill: black;
  stroke: none; }

.actor-line {
  stroke: lightgrey; }

.messageLine0 {
  stroke-width: 1.5;
  stroke-dasharray: '2 2';
  stroke: lightgrey; }

.messageLine1 {
  stroke-width: 1.5;
  stroke-dasharray: '2 2';
  stroke: lightgrey; }

#arrowhead {
  fill: lightgrey; }

.sequenceNumber {
  fill: white; }

#sequencenumber {
  fill: lightgrey; }

#crosshead path {
  fill: lightgrey !important;
  stroke: lightgrey !important; }

.messageText {
  fill: lightgrey;
  stroke: none; }

.labelBox {
  stroke: #81B1DB;
  fill: #BDD5EA; }

.labelText {
  fill: #323D47;
  stroke: none; }

.loopText {
  fill: lightgrey;
  stroke: none; }

.loopLine {
  stroke-width: 2;
  stroke-dasharray: '2 2';
  stroke: #81B1DB; }

.note {
  stroke: rgba(255, 255, 255, 0.25);
  fill: #fff5ad; }

.noteText {
  fill: black;
  stroke: none;
  
  font-size: 14px; }

.activation0 {
  fill: #f4f4f4;
  stroke: #666; }

.activation1 {
  fill: #f4f4f4;
  stroke: #666; }

.activation2 {
  fill: #f4f4f4;
  stroke: #666; }

/** Section styling */
.section {
  stroke: none;
  opacity: 0.2; }

.section0 {
  fill: rgba(255, 255, 255, 0.3); }

.section2 {
  fill: #EAE8B9; }

.section1,
.section3 {
  fill: white;
  opacity: 0.2; }

.sectionTitle0 {
  fill: #F9FFFE; }

.sectionTitle1 {
  fill: #F9FFFE; }

.sectionTitle2 {
  fill: #F9FFFE; }

.sectionTitle3 {
  fill: #F9FFFE; }

.sectionTitle {
  text-anchor: start;
  font-size: 11px;
  text-height: 14px;
   }

/* Grid and axis */
.grid .tick {
  stroke: lightgrey;
  opacity: 0.3;
  shape-rendering: crispEdges; }

.grid path {
  stroke-width: 0; }

/* Today line */
.today {
  fill: none;
  stroke: #DB5757;
  stroke-width: 2px; }

/* Task styling */
/* Default task */
.task {
  stroke-width: 2; }

.taskText {
  text-anchor: middle;
   }

.taskText:not([font-size]) {
  font-size: 11px; }

.taskTextOutsideRight {
  fill: #323D47;
  text-anchor: start;
  font-size: 11px;
   }

.taskTextOutsideLeft {
  fill: #323D47;
  text-anchor: end;
  font-size: 11px; }

/* Special case clickable */
.task.clickable {
  cursor: pointer; }

.taskText.clickable {
  cursor: pointer;
  fill: #003163 !important;
  font-weight: bold; }

.taskTextOutsideLeft.clickable {
  cursor: pointer;
  fill: #003163 !important;
  font-weight: bold; }

.taskTextOutsideRight.clickable {
  cursor: pointer;
  fill: #003163 !important;
  font-weight: bold; }

/* Specific task settings for the sections*/
.taskText0,
.taskText1,
.taskText2,
.taskText3 {
  fill: #323D47; }

.task0,
.task1,
.task2,
.task3 {
  fill: #BDD5EA;
  stroke: rgba(255, 255, 255, 0.5); }

.taskTextOutside0,
.taskTextOutside2 {
  fill: lightgrey; }

.taskTextOutside1,
.taskTextOutside3 {
  fill: lightgrey; }

/* Active task */
.active0,
.active1,
.active2,
.active3 {
  fill: #81B1DB;
  stroke: rgba(255, 255, 255, 0.5); }

.activeText0,
.activeText1,
.activeText2,
.activeText3 {
  fill: #323D47 !important; }

/* Completed task */
.done0,
.done1,
.done2,
.done3 {
  stroke: grey;
  fill: lightgrey;
  stroke-width: 2; }

.doneText0,
.doneText1,
.doneText2,
.doneText3 {
  fill: #323D47 !important; }

/* Tasks on the critical line */
.crit0,
.crit1,
.crit2,
.crit3 {
  stroke: #E83737;
  fill: #E83737;
  stroke-width: 2; }

.activeCrit0,
.activeCrit1,
.activeCrit2,
.activeCrit3 {
  stroke: #E83737;
  fill: #81B1DB;
  stroke-width: 2; }

.doneCrit0,
.doneCrit1,
.doneCrit2,
.doneCrit3 {
  stroke: #E83737;
  fill: lightgrey;
  stroke-width: 2;
  cursor: pointer;
  shape-rendering: crispEdges; }

.milestone {
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.milestoneText {
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.activeCritText3 {
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.titleText {
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g.classGroup text {
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  font-size: 10px; }
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g.classGroup rect {
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g.classGroup line {
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.classLabel .box {
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  fill: #BDD5EA;
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.classLabel .label {
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  font-size: 10px; }

.relation {
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  fill: none; }

#compositionStart {
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#compositionEnd {
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#aggregationStart {
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#aggregationEnd {
  fill: #BDD5EA;
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#dependencyStart {
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#dependencyEnd {
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#extensionStart {
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  stroke-width: 1; }

#extensionEnd {
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  stroke-width: 1; }

.commit-id,
.commit-msg,
.branch-label {
  fill: lightgrey;
  color: lightgrey;
   }

.pieTitleText {
  text-anchor: middle;
  font-size: 25px;
  fill: #eee;
}

.slice {
   }

g.stateGroup text {
  fill: #eee;
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  font-size: 10px;
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g.stateGroup circle {
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}

g.stateGroup .state-title {
  font-weight: bolder;
  fill: black; }

g.stateGroup rect {
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g.stateGroup line {
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.transition {
  stroke: #9370DB;
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  fill: none; }

.stateGroup .composit {
  fill: #555;
  border-bottom: 1px; }

.state-note {
  stroke: rgba(255, 255, 255, 0.25);
  fill: #fff5ad; }
  .state-note text {
    fill: black;
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    font-size: 10px; }

.stateLabel .box {
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  fill: #BDD5EA;
  opacity: 0.5; }

.stateLabel text {
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}


/* CSS Document */

/** code highlight */

.cm-s-inner .cm-variable,
.cm-s-inner .cm-operator,
.cm-s-inner .cm-property {
    color: #b8bfc6;
}

.cm-s-inner .cm-keyword {
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}

.cm-s-inner .cm-tag {
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}

.cm-s-inner .cm-attribute {
    color: #7575E4;
}

.CodeMirror div.CodeMirror-cursor {
    border-left: 1px solid #b8bfc6;
    z-index: 3;
}

.cm-s-inner .cm-string {
    color: #D26B6B;
}

.cm-s-inner .cm-comment,
.cm-s-inner.cm-comment {
    color: #DA924A;
}

.cm-s-inner .cm-header,
.cm-s-inner .cm-def,
.cm-s-inner.cm-header,
.cm-s-inner.cm-def {
    color: #8d8df0;
}

.cm-s-inner .cm-quote,
.cm-s-inner.cm-quote {
    color: #57ac57;
}

.cm-s-inner .cm-hr {
    color: #d8d5d5;
}

.cm-s-inner .cm-link {
    color: #d3d3ef;
}

.cm-s-inner .cm-negative {
    color: #d95050;
}

.cm-s-inner .cm-positive {
    color: #50e650;
}

.cm-s-inner .cm-string-2 {
    color: #f50;
}

.cm-s-inner .cm-meta,
.cm-s-inner .cm-qualifier {
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}

.cm-s-inner .cm-builtin {
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}

.cm-s-inner .cm-bracket {
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}

.cm-s-inner .cm-atom,
.cm-s-inner.cm-atom {
    color: #84B6CB;
}

.cm-s-inner .cm-number {
    color: #64AB8F;
}

.cm-s-inner .cm-variable {
    color: #b8bfc6;
}

.cm-s-inner .cm-variable-2 {
    color: #9FBAD5;
}

.cm-s-inner .cm-variable-3 {
    color: #1cc685;
}

.CodeMirror-selectedtext,
.CodeMirror-selected {
    background: #4a89dc;
    color: #fff !important;
    text-shadow: none;
}

.CodeMirror-gutters {
    border-right: none;
}

/* CSS Document */

/** markdown source **/
.cm-s-typora-default .cm-header, 
.cm-s-typora-default .cm-property
{
    color: #cebcca;
}

.CodeMirror.cm-s-typora-default div.CodeMirror-cursor{
    border-left: 3px solid #b8bfc6;
}

.cm-s-typora-default .cm-comment {
    color: #9FB1FF;
}

.cm-s-typora-default .cm-string {
    color: #A7A7D9
}

.cm-s-typora-default .cm-atom, .cm-s-typora-default .cm-number {
    color: #848695;
    font-style: italic;
}

.cm-s-typora-default .cm-link {
    color: #95B94B;
}

.cm-s-typora-default .CodeMirror-activeline-background {
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}

.cm-s-typora-default .cm-comment, .cm-s-typora-default .cm-code {
	color: #8aa1e1;
}@import "";
@import "";
@import "";

:root {
    --bg-color: #003163; /*#363B40;*/
    --side-bar-bg-color: #2E3033;
    --text-color: #b8bfc6;

    --select-text-bg-color:#4a89dc;

    --item-hover-bg-color: #0a0d16;
    --control-text-color: #b7b7b7;
    --control-text-hover-color: #eee;
    --window-border: 1px solid #555;

    --active-file-bg-color: rgb(34, 34, 34);
    --active-file-border-color: #8d8df0;

    --primary-color: #a3d5fe;

    --active-file-text-color: white;
    --item-hover-bg-color: #70717d;
    --item-hover-text-color: white;
    --primary-color: #6dc1e7;

    --rawblock-edit-panel-bd: #333;

    --search-select-bg-color: #428bca;
}

html {
    font-size: 16px;
}

html,
body {
    -webkit-text-size-adjust: 100%;
    -ms-text-size-adjust: 100%;
    background: #003163; /* #363B40; */
    background: var(--bg-color);
    fill: currentColor;
    line-height: 1.625rem;
}

#write {
    max-width: 914px;
}


@media only screen and (min-width: 1400px) {
	#write {
		max-width: 1024px;
	}
}

@media only screen and (min-width: 1800px) {
	#write {
		max-width: 1200px;
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}

html,
body,
button,
input,
select,
textarea,
div.code-tooltip-content {
    color: #b8bfc6;
    border-color: transparent;
}

div.code-tooltip,
.md-hover-tip .md-arrow:after {
    background: #333;
}

.popover.bottom > .arrow:after {
    border-bottom-color: #333;
}

html,
body,
button,
input,
select,
textarea {
    font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
}

hr {
    height: 2px;
    border: 0;
    margin: 24px 0 !important;
}

h1,
h2,
h3,
h4,
h5,
h6 {
    font-family: "Lucida Grande", "Corbel", sans-serif;
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    clear: both;
    -ms-word-wrap: break-word;
    word-wrap: break-word;
    margin: 0;
    padding: 0;
    color: #DEDEDE
}

h1 {
    font-size: 2.5rem;
    /* 36px */
    line-height: 2.75rem;
    /* 40px */
    margin-bottom: 1.5rem;
    /* 24px */
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}

h2 {
    font-size: 1.63rem;
    /* 24px */
    line-height: 1.875rem;
    /* 30px */
    margin-bottom: 1.5rem;
    /* 24px */
    letter-spacing: -1px;
    font-weight: bold;
}

h3 {
    font-size: 1.17rem;
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    line-height: 1.5rem;
    /* 24px */
    margin-bottom: 1.5rem;
    /* 24px */
    letter-spacing: -1px;
    font-weight: bold;
}

h4 {
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    /* 16px */
    line-height: 1.375rem;
    /* 22px */
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    /* 24px */
    color: white;
}

h5 {
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}

h6 {
    font-size: 0.93rem;
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    /* 16px */
    margin-bottom: 0.75rem;
    color: white;
}

@media (min-width: 980px) {
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    h4.md-focus:before,
    h5.md-focus:before,
    h6.md-focus:before {
        color: #ddd;
        border: 1px solid #ddd;
        border-radius: 3px;
        position: absolute;
        left: -1.642857143rem;
        top: .357142857rem;
        float: left;
        font-size: 9px;
        padding-left: 2px;
        padding-right: 2px;
        vertical-align: bottom;
        font-weight: normal;
        line-height: normal;
    }

    h3.md-focus:before {
        content: 'h3';
    }

    h4.md-focus:before {
        content: 'h4';
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    h5.md-focus:before {
        content: 'h5';
        top: 0px;
    }

    h6.md-focus:before {
        content: 'h6';
        top: 0px;
    }
}

a {
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    outline: 0;
}

a:hover {
    outline: 0;
}

a:focus {
    outline: thin dotted;
}

sup.md-footnote {
    background-color: #555;
    color: #ddd;
}

p {
    -ms-word-wrap: break-word;
    word-wrap: break-word;
}

p,
ul,
dd,
ol,
hr,
address,
pre,
table,
iframe,
.wp-caption,
.wp-audio-shortcode,
.wp-video-shortcode {
    margin-top: 0;
    margin-bottom: 1.5rem;
    /* 24px */
}

li > blockquote {
	margin-bottom: 0;
}

audio:not([controls]) {
    display: none;
}

[hidden] {
    display: none;
}

::-moz-selection {
    background: #4a89dc;
    color: #fff;
    text-shadow: none;
}

*.in-text-selection,
::selection {
    background: #4a89dc;
    color: #fff;
    text-shadow: none;
}

ul,
ol {
    padding: 0 0 0 1.875rem;
    /* 30px */
}

ul {
    list-style: square;
}

ol {
    list-style: decimal;
}

ul ul,
ol ol,
ul ol,
ol ul {
    margin: 0;
}

b,
th,
dt,
strong {
    font-weight: bold;
}

i,
em,
dfn,
cite {
    font-style: italic;
}

blockquote {
    padding-left: 1.875rem;
    margin: 0 0 1.875rem 1.875rem;
    border-left: solid 2px #474d54;
    padding-left: 30px;
    margin-top: 35px;
}

pre,
code,
kbd,
tt,
var {
    font-size: 0.875rem;
    font-family: Monaco, Consolas, "Andale Mono", "DejaVu Sans Mono", monospace;
}

code,
tt,
var {
    background: rgba(0, 0, 0, 0.05);
}

kbd {
    padding: 2px 4px;
    font-size: 90%;
    color: #fff;
    background-color: #333;
    border-radius: 3px;
    box-shadow: inset 0 -1px 0 rgba(0,0,0,.25);
}

pre.md-fences {
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    margin-bottom: 20px;
    background: #333;
}

.CodeMirror-gutters {
    background: #333;
    border-right: 1px solid transparent;
}

.enable-diagrams pre.md-fences[lang="sequence"] .code-tooltip,
.enable-diagrams pre.md-fences[lang="flow"] .code-tooltip,
.enable-diagrams pre.md-fences[lang="mermaid"] .code-tooltip {
    bottom: -2.2em;
    right: 4px;
}

code,
kbd,
tt,
var {
    padding: 2px 5px;
}

table {
    max-width: 100%;
    width: 100%;
    border-collapse: collapse;
    border-spacing: 0;
}

th,
td {
    padding: 5px 10px;
    vertical-align: top;
}

a {
    -webkit-transition: all .2s ease-in-out;
    transition: all .2s ease-in-out;
}

hr {
    background: #474d54;
    /* variable */
}

h1 {
    margin-top: 2em;
}

a {
    color: #e0e0e0;
    text-decoration: underline;
}

a:hover {
    color: #fff;
}

.md-inline-math script {
    color: #81b1db;
}

b,
th,
dt,
strong {
    color: #DEDEDE;
    /* variable */
}

mark {
    background: #D3D40E;
}

blockquote {
    color: #9DA2A6;
}

table a {
    color: #DEDEDE;
    /* variable */
}

th,
td {
    border: solid 1px #474d54;
    /* variable */
}

.task-list {
    padding-left: 0;
}

.md-task-list-item {
    padding-left: 1.25rem;
}

.md-task-list-item > input {
    top: auto;
}

.md-task-list-item > input:before {
    content: "";
    display: inline-block;
    width: 0.875rem;
    height: 0.875rem;
    vertical-align: middle;
    text-align: center;
    border: 1px solid #b8bfc6;
    background-color: #363B40;
    margin-top: -0.4rem;
}

.md-task-list-item > input:checked:before,
.md-task-list-item > input[checked]:before {
    content: '\221A';
    /*◘*/
    font-size: 0.625rem;
    line-height: 0.625rem;
    color: #DEDEDE;
}

/** quick open **/
.auto-suggest-container {
    border: 0px;
    background-color: #525C65;
}

#typora-quick-open {
    background-color: #525C65;
}

#typora-quick-open input{
    background-color: #525C65;
    border: 0;
    border-bottom: 1px solid grey;
}

.typora-quick-open-item {
    background-color: inherit;
    color: inherit;
}

.typora-quick-open-item.active,
.typora-quick-open-item:hover {
    background-color: #4D8BDB;
    color: white;
}

.typora-quick-open-item:hover {
    background-color: rgba(77, 139, 219, 0.8);
}

.typora-search-spinner > div {
  background-color: #fff;
}

#write pre.md-meta-block {
    border-bottom: 1px dashed #ccc;
    background: transparent;
    padding-bottom: 0.6em;
    line-height: 1.6em;
}

.btn,
.btn .btn-default {
    background: transparent;
    color: #b8bfc6;
}

.ty-table-edit {
    border-top: 1px solid gray;
    background-color: #363B40;
}

.popover-title {
    background: transparent;
}

.md-image>.md-meta {
    color: #BBBBBB;
    background: transparent;
}

.md-expand.md-image>.md-meta {
    color: #DDD;
}

#write>h3:before,
#write>h4:before,
#write>h5:before,
#write>h6:before {
    border: none;
    border-radius: 0px;
    color: #888;
    text-decoration: underline;
    left: -1.4rem;
    top: 0.2rem;
}

#write>h3.md-focus:before {
    top: 2px;
}

#write>h4.md-focus:before {
    top: 2px;
}

.md-toc-item {
    color: #A8C2DC;
}

#write div.md-toc-tooltip {
    background-color: #363B40;
}

.dropdown-menu .btn:hover,
.dropdown-menu .btn:focus,
.md-toc .btn:hover,
.md-toc .btn:focus {
    color: white;
    background: black;
}

#toc-dropmenu {
    background: rgba(50, 54, 59, 0.93);
    border: 1px solid rgba(253, 253, 253, 0.15);
}

#toc-dropmenu .divider {
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}

.outline-expander:before {
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}

#typora-sidebar {
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    border-right: 1px dashed;
    border-right: none;
}

.sidebar-tabs {
    border-bottom:0;
}

#typora-sidebar:hover .outline-title-wrapper {
    border-left: 1px dashed;
}

.outline-title-wrapper .btn {
    color: inherit;
}

.outline-item:hover {
    border-color: #363B40;
    background-color: #363B40;
    color: white;
}

h1.md-focus .md-attr,
h2.md-focus .md-attr,
h3.md-focus .md-attr,
h4.md-focus .md-attr,
h5.md-focus .md-attr,
h6.md-focus .md-attr,
.md-header-span .md-attr {
    color: #8C8E92;
    display: inline;
}

.md-comment {
    color: #5a95e3;
    opacity: 1;
}

.md-inline-math svg {
    color: #b8bfc6;
}

#math-inline-preview .md-arrow:after {
    background: black;
}

.modal-content {
    background: var(--bg-color);
    border: 0;
}

.modal-title {
    font-size: 1.5em;
}

.modal-content input {
    background-color: rgba(26, 21, 21, 0.51);
    color: white;
}

.modal-content .input-group-addon {
    color: white;
}

.modal-backdrop {
    background-color: rgba(174, 174, 174, 0.7);
}

.modal-content .btn-primary {
    border-color: var(--primary-color);
}

.md-table-resize-popover {
    background-color: #333;
}

.form-inline .input-group .input-group-addon {
    color: white;
}

#md-searchpanel {
    border-bottom: 1px dashed grey;
}

/** UI for electron */

.context-menu,
#spell-check-panel,
#footer-word-count-info {
    background-color: #42464A;
}

.context-menu.dropdown-menu .divider,
.dropdown-menu .divider {
    background-color: #777777;
}

footer {
    color: inherit;
}

@media (max-width: 1000px) {
    footer {
        border-top: none;
    }
    footer:hover {
        color: inherit;
    }
}

#file-info-file-path .file-info-field-value:hover {
    background-color: #555;
    color: #dedede;
}

.megamenu-content,
.megamenu-opened header {
    background: var(--bg-color);
}

.megamenu-menu-panel h2,
.megamenu-menu-panel h1,
.long-btn {
    color: inherit;
}

.megamenu-menu-panel input[type='text'] {
    background: inherit;
    border: 0;
    border-bottom: 1px solid;
}

#recent-file-panel-action-btn {
    background: inherit;
    border: 1px grey solid;
}

.megamenu-menu-panel .dropdown-menu > li > a {
    color: inherit;
    background-color: #2F353A;
    text-decoration: none;
}

.megamenu-menu-panel table td:nth-child(1) {
    color: inherit;
    font-weight: bold;
}

.megamenu-menu-panel tbody tr:hover td:nth-child(1) {
    color: white;
}

.modal-footer .btn-default, 
.modal-footer .btn-primary,
.modal-footer .btn-default:not(:hover) {
    border: 1px solid;
    border-color: transparent;
}

.btn-default:hover, .btn-default:focus, .btn-default.focus, .btn-default:active, .btn-default.active, .open > .dropdown-toggle.btn-default {
    color: white;
    border: 1px solid #ddd;
    background-color: inherit;
}

.modal-header {
    border-bottom: 0;
}

.modal-footer {
    border-top: 0;
}

#recent-file-panel tbody tr:nth-child(2n-1) {
    background-color: transparent !important;
}

.megamenu-menu-panel tbody tr:hover td:nth-child(2) {
    color: inherit;
}

.megamenu-menu-panel .btn {
    border: 1px solid #eee;
    background: transparent;
}

.mouse-hover .toolbar-icon.btn:hover,
#w-full.mouse-hover,
#w-pin.mouse-hover {
    background-color: inherit;
}

.typora-node::-webkit-scrollbar {
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}

.typora-node::-webkit-scrollbar-thumb:vertical {
    background: rgba(250, 250, 250, 0.3);
}

.typora-node::-webkit-scrollbar-thumb:vertical:active {
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}

#w-unpin {
    background-color: #4182c4;
}

#top-titlebar, #top-titlebar * {
    color: var(--item-hover-text-color);
}

.typora-sourceview-on #toggle-sourceview-btn,
#footer-word-count:hover,
.ty-show-word-count #footer-word-count {
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}

#toggle-sourceview-btn:hover {
    color: #eee;
    background: #333333;
}

/** focus mode */
.on-focus-mode .md-end-block:not(.md-focus):not(.md-focus-container) * {
    color: #686868 !important;
}

.on-focus-mode .md-end-block:not(.md-focus) img,
.on-focus-mode .md-task-list-item:not(.md-focus-container)>input {
    opacity: #686868 !important;
}

.on-focus-mode li[cid]:not(.md-focus-container){
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}

.on-focus-mode .md-fences.md-focus .CodeMirror-code>*:not(.CodeMirror-activeline) *,
.on-focus-mode .CodeMirror.cm-s-inner:not(.CodeMirror-focused) * {
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<div  id='write'  class = 'is-node'><h1><a name="js-toolbox" class="md-header-anchor"></a><span>JS-Toolbox</span></h1><div class='md-toc' mdtype='toc'><p class="md-toc-content" role="list"><span role="listitem" class="md-toc-item md-toc-h1" data-ref="n0"><a class="md-toc-inner" href="#js-toolbox">JS-Toolbox</a></span><span role="listitem" class="md-toc-item md-toc-h2" data-ref="n3"><a class="md-toc-inner" href="#1-intro--functions">1. Intro &amp; Functions</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n6"><a class="md-toc-inner" href="#canvas">Canvas</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n8"><a class="md-toc-inner" href="#key-events">Key events</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n10"><a class="md-toc-inner" href="#game-loop">Game loop</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n12"><a class="md-toc-inner" href="#fundamentals-of-lambda-calculus--functional-programming-in-javascript---youtube-video">Fundamentals of Lambda Calculus &amp; Functional Programming in JavaScript - YouTube Video</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n14"><a class="md-toc-inner" href="#example">Example</a></span><span role="listitem" class="md-toc-item md-toc-h2" data-ref="n18"><a class="md-toc-inner" href="#2-lambda">2. Lambda</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n19"><a class="md-toc-inner" href="#javascript-variables">JavaScript Variables</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n22"><a class="md-toc-inner" href="#iife">IIFE</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n26"><a class="md-toc-inner" href="#alpha-translation">Alpha Translation</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n28"><a class="md-toc-inner" href="#beta-reduktion">Beta Reduktion</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n30"><a class="md-toc-inner" href="#eta-reduktion">Eta Reduktion</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n32"><a class="md-toc-inner" href="#examples">Examples</a></span><span role="listitem" class="md-toc-item md-toc-h2" data-ref="n42"><a class="md-toc-inner" href="#3-algebraic-data-types">3. Algebraic Data Types</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n48"><a class="md-toc-inner" href="#atomic-lamda-terms">Atomic Lamda Terms</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n50"><a class="md-toc-inner" href="#pair-product-type">Pair, Product Type</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n52"><a class="md-toc-inner" href="#pair-encoding">Pair encoding</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n54"><a class="md-toc-inner" href="#either-co-product-sum">Either, Co-Product, Sum</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n56"><a class="md-toc-inner" href="#special-case-maybe">Special Case: Maybe</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n58"><a class="md-toc-inner" href="#example-n58">Example</a></span><span role="listitem" class="md-toc-item md-toc-h2" data-ref="n61"><a class="md-toc-inner" href="#4-map-filter-reduce">4. Map, Filter, Reduce</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n67"><a class="md-toc-inner" href="#map">Map</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n69"><a class="md-toc-inner" href="#filter">Filter</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n71"><a class="md-toc-inner" href="#reduce">Reduce</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n73"><a class="md-toc-inner" href="#examples-n73">Examples</a></span><span role="listitem" class="md-toc-item md-toc-h2" data-ref="n77"><a class="md-toc-inner" href="#5-scripting-pwa-plotter-excel">5. Scripting, PWA, Plotter, Excel</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n83"><a class="md-toc-inner" href="#why-scripting">Why Scripting?</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n109"><a class="md-toc-inner" href="#progressive-web-app">Progressive Web App</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n111"><a class="md-toc-inner" href="#function-plotter-eval">Function Plotter: eval</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n114"><a class="md-toc-inner" href="#function-plotter-function">Function Plotter: Function()</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n118"><a class="md-toc-inner" href="#scripting-caution">Scripting Caution</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n121"><a class="md-toc-inner" href="#examples-n121">Examples</a></span><span role="listitem" class="md-toc-item md-toc-h2" data-ref="n127"><a class="md-toc-inner" href="#6-objects">6. Objects</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n133"><a class="md-toc-inner" href="#open--dynamic">Open &amp; dynamic</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n136"><a class="md-toc-inner" href="#closed--explicit">Closed &amp; explicit</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n139"><a class="md-toc-inner" href="#mixed--classified">Mixed &amp; classified</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n143"><a class="md-toc-inner" href="#example-n143">Example</a></span><span role="listitem" class="md-toc-item md-toc-h2" data-ref="n147"><a class="md-toc-inner" href="#7-classes">7. Classes</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n153"><a class="md-toc-inner" href="#class-keyword"><code>class</code> Keyword</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n155"><a class="md-toc-inner" href="#extends-keyword"><code>extends</code> Keyword</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n157"><a class="md-toc-inner" href="#prototype-chain">Prototype chain</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n159"><a class="md-toc-inner" href="#example-n159">Example</a></span><span role="listitem" class="md-toc-item md-toc-h2" data-ref="n163"><a class="md-toc-inner" href="#8-moves-user-interfaces">8. Moves, User Interfaces</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n169"><a class="md-toc-inner" href="#compare-with-dancing">Compare with Dancing</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n175"><a class="md-toc-inner" href="#recognize-moves">Recognize Moves</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n181"><a class="md-toc-inner" href="#task-1-improve-the-tests">Task 1: Improve the Tests</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n189"><a class="md-toc-inner" href="#task-2-todo-list-example">Task 2: Todo List Example</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n195"><a class="md-toc-inner" href="#moves---your-choice">Moves - Your Choice</a></span><span role="listitem" class="md-toc-item md-toc-h4" data-ref="n196"><a class="md-toc-inner" href="#0-explore">0: Explore</a></span><span role="listitem" class="md-toc-item md-toc-h4" data-ref="n204"><a class="md-toc-inner" href="#1-start-at-the-end">1: Start at the End</a></span><span role="listitem" class="md-toc-item md-toc-h4" data-ref="n210"><a class="md-toc-inner" href="#2-extract">2: Extract</a></span><span role="listitem" class="md-toc-item md-toc-h4" data-ref="n216"><a class="md-toc-inner" href="#3-abstract">3: Abstract</a></span><span role="listitem" class="md-toc-item md-toc-h4" data-ref="n224"><a class="md-toc-inner" href="#4-reorganize">4: Reorganize</a></span><span role="listitem" class="md-toc-item md-toc-h4" data-ref="n232"><a class="md-toc-inner" href="#5-release">5: Release</a></span><span role="listitem" class="md-toc-item md-toc-h4" data-ref="n240"><a class="md-toc-inner" href="#6-retrospective">6: Retrospective</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n246"><a class="md-toc-inner" href="#observations">Observations</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n254"><a class="md-toc-inner" href="#example-n254">Example</a></span><span role="listitem" class="md-toc-item md-toc-h2" data-ref="n258"><a class="md-toc-inner" href="#9-ui-engineering-mvc">9. UI Engineering, MVC</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n264"><a class="md-toc-inner" href="#callback---hof">Callback - HOF</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n267"><a class="md-toc-inner" href="#observable">Observable</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n269"><a class="md-toc-inner" href="#mvc">MVC</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n271"><a class="md-toc-inner" href="#example-n271">Example</a></span><span role="listitem" class="md-toc-item md-toc-h2" data-ref="n275"><a class="md-toc-inner" href="#10-async-programming">10. Async Programming</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n281"><a class="md-toc-inner" href="#testing">Testing</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n283"><a class="md-toc-inner" href="#callback-events">Callback, Events</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n285"><a class="md-toc-inner" href="#promise">Promise</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n290"><a class="md-toc-inner" href="#async--await">Async / Await</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n294"><a class="md-toc-inner" href="#example-n294">Example</a></span><span role="listitem" class="md-toc-item md-toc-h2" data-ref="n298"><a class="md-toc-inner" href="#11-data-flow">11. Data Flow</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n299"><a class="md-toc-inner" href="#coordination-schemata">Coordination schemata</a></span><span role="listitem" class="md-toc-item md-toc-h4" data-ref="n309"><a class="md-toc-inner" href="#no-coordination">No Coordination</a></span><span role="listitem" class="md-toc-item md-toc-h4" data-ref="n317"><a class="md-toc-inner" href="#sequence">Sequence</a></span><span role="listitem" class="md-toc-item md-toc-h4" data-ref="n325"><a class="md-toc-inner" href="#result-dependency">Result Dependency</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n333"><a class="md-toc-inner" href="#scheduler-idea">Scheduler Idea</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n339"><a class="md-toc-inner" href="#dataflowvariable">DataFlowVariable</a></span><span role="listitem" class="md-toc-item md-toc-h2" data-ref="n348"><a class="md-toc-inner" href="#12-modules">12. Modules</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n354"><a class="md-toc-inner" href="#why-modules">Why Modules?</a></span><span role="listitem" class="md-toc-item md-toc-h4" data-ref="n363"><a class="md-toc-inner" href="#distinguish">Distinguish</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n369"><a class="md-toc-inner" href="#es6-modules">ES6 Modules</a></span><span role="listitem" class="md-toc-item md-toc-h4" data-ref="n380"><a class="md-toc-inner" href="#package-manager">Package Manager</a></span><span role="listitem" class="md-toc-item md-toc-h4" data-ref="n382"><a class="md-toc-inner" href="#build-tools">Build Tools</a></span><span role="listitem" class="md-toc-item md-toc-h4" data-ref="n384"><a class="md-toc-inner" href="#legacy-module-systems">Legacy module systems</a></span><span role="listitem" class="md-toc-item md-toc-h4" data-ref="n386"><a class="md-toc-inner" href="#legacy-module-loader--bundler">Legacy Module Loader / Bundler</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n388"><a class="md-toc-inner" href="#modules-are-async">Modules are async</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n390"><a class="md-toc-inner" href="#import-variants">Import Variants</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n393"><a class="md-toc-inner" href="#export-variants">Export Variants</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n396"><a class="md-toc-inner" href="#impacts">Impacts</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n408"><a class="md-toc-inner" href="#sop---single-origin-policy">SOP - Single Origin Policy</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n414"><a class="md-toc-inner" href="#useful-tools">Useful Tools</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n426"><a class="md-toc-inner" href="#resources">Resources</a></span><span role="listitem" class="md-toc-item md-toc-h2" data-ref="n433"><a class="md-toc-inner" href="#13-transpilers-typescript-purescript-elm">13. Transpilers: TypeScript, PureScript, Elm</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n439"><a class="md-toc-inner" href="#what-they-have-in-common">What they have in common</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n452"><a class="md-toc-inner" href="#the-cycle">The Cycle</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n454"><a class="md-toc-inner" href="#typescript">TypeScript</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n464"><a class="md-toc-inner" href="#elm">Elm</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n476"><a class="md-toc-inner" href="#purescript--pux">PureScript / Pux</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n486"><a class="md-toc-inner" href="#calling-javascript-ffi">Calling JavaScript (FFI)</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n497"><a class="md-toc-inner" href="#applicability">Applicability</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n508"><a class="md-toc-inner" href="#paradigm">Paradigm</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n519"><a class="md-toc-inner" href="#approach">Approach</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n530"><a class="md-toc-inner" href="#cool">Cool</a></span><span role="listitem" class="md-toc-item md-toc-h3" data-ref="n541"><a class="md-toc-inner" href="#more-transpilers">More Transpilers</a></span><span role="listitem" class="md-toc-item md-toc-h2" data-ref="n559"><a class="md-toc-inner" href="#14-crazy-javascript">14. Crazy JavaScript</a></span></p></div><h2><a name="1-intro--functions" class="md-header-anchor"></a><span>1. Intro &amp; Functions</span></h2><blockquote><p><span>&quot;You only understand what you can build by yourself =&gt; use no dependencies&quot;</span></p></blockquote><h3><a name="canvas" class="md-header-anchor"></a><span>Canvas</span></h3><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation" style=""><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">canvas</span> <span class="cm-operator">=</span> <span class="cm-variable">document</span>.<span class="cm-property">getElementById</span>(<span class="cm-string">"canvas"</span>);</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">context</span> <span class="cm-operator">=</span> <span class="cm-variable">canvas</span>.<span class="cm-property">getContext</span>(<span class="cm-string">"2d"</span>);</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span cm-text="">​</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-variable">context</span>.<span class="cm-property">fillStyle</span> <span class="cm-operator">=</span> <span class="cm-string">"black"</span>;</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-variable">context</span>.<span class="cm-property">fillRect</span>(<span class="cm-number">0</span>, <span class="cm-number">0</span>, <span class="cm-variable">canvas</span>.<span class="cm-property">width</span>, <span class="cm-variable">canvas</span>.<span class="cm-property">height</span>);</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 88px;"></div><div class="CodeMirror-gutters" style="display: none; height: 88px;"></div></div></div></pre><h3><a name="key-events" class="md-header-anchor"></a><span>Key events</span></h3><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation" style=""><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">rightArrow</span> <span class="cm-operator">=</span> <span class="cm-number">39</span>;</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">leftArrow</span> <span class="cm-operator">=</span> <span class="cm-number">37</span>;</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-variable">window</span>.<span class="cm-property">onkeydown</span> <span class="cm-operator">=</span> <span class="cm-def">evt</span> <span class="cm-operator">=&gt;</span> {</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span>(<span class="cm-variable-2">evt</span>.<span class="cm-property">keyCode</span> <span class="cm-operator">===</span> <span class="cm-variable">rightArrow</span>) <span class="cm-operator">?</span> <span class="cm-variable">…</span> : <span class="cm-variable">…</span> ;</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">};</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 88px;"></div><div class="CodeMirror-gutters" style="display: none; height: 88px;"></div></div></div></pre><h3><a name="game-loop" class="md-header-anchor"></a><span>Game loop</span></h3><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-variable">setInterval</span>( () <span class="cm-operator">=&gt;</span> {</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-variable">nextBoard</span>();</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-variable">display</span>(<span class="cm-variable">context</span>);</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">}, <span class="cm-number">1000</span> <span class="cm-operator">/</span> <span class="cm-number">5</span>);</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 70px;"></div><div class="CodeMirror-gutters" style="display: none; height: 70px;"></div></div></div></pre><h3><a name="fundamentals-of-lambda-calculus--functional-programming-in-javascript---youtube-video" class="md-header-anchor"></a><span>Fundamentals of Lambda Calculus &amp; Functional Programming in JavaScript - YouTube Video</span></h3><p><a href='https://www.youtube.com/watch?v=3VQ382QG-y4'><span>Video-Link</span></a></p><h3><a name="example" class="md-header-anchor"></a><span>Example</span></h3><p><span>A function </span><code>plus</code><span> that returns the sum of its arguments:</span></p><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">plus</span> <span class="cm-operator">=</span> <span class="cm-def">x</span> <span class="cm-operator">=&gt;</span> <span class="cm-def">y</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">x</span> <span class="cm-operator">+</span> <span class="cm-variable-2">y</span>;</span></pre></div></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 18px;"></div><div class="CodeMirror-gutters" style="display: none; height: 18px;"></div></div></div></pre><p>&nbsp;</p><h2><a name="2-lambda" class="md-header-anchor"></a><span>2. Lambda</span></h2><h3><a name="javascript-variables" class="md-header-anchor"></a><span>JavaScript Variables</span></h3><p><span>Only use </span><code>let</code><span> and </span><code>const</code><span>:</span></p><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">let</span> <span class="cm-def">x</span> <span class="cm-operator">=</span> <span class="cm-meta">...</span>; <span class="cm-tab" role="presentation" cm-text="	">   </span><span class="cm-comment">// mutable, &nbsp; local scope</span></span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">x</span> <span class="cm-operator">=</span> <span class="cm-meta">...</span>; <span class="cm-tab" role="presentation" cm-text="	"> </span><span class="cm-comment">// immutable, local scope</span></span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 35px;"></div><div class="CodeMirror-gutters" style="display: none; height: 35px;"></div></div></div></pre><h3><a name="iife" class="md-header-anchor"></a><span>IIFE</span></h3><blockquote><p><span>immediately invoked function expression</span></p></blockquote><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">function</span> <span class="cm-def">foo</span>() {..}; <span class="cm-variable">foo</span>()</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">( <span class="cm-keyword">function</span> <span class="cm-def">foo</span>() {..} ) ()</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">( <span class="cm-keyword">function</span>() {..} ) ()</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">( () <span class="cm-operator">=&gt;</span> {..} ) ()</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 70px;"></div><div class="CodeMirror-gutters" style="display: none; height: 70px;"></div></div></div></pre><h3><a name="alpha-translation" class="md-header-anchor"></a><span>Alpha Translation</span></h3><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">id</span> <span class="cm-operator">=</span> <span class="cm-def">x</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">x</span></span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">id</span> <span class="cm-operator">=</span> <span class="cm-def">y</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">y</span></span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 35px;"></div><div class="CodeMirror-gutters" style="display: none; height: 35px;"></div></div></div></pre><h3><a name="beta-reduktion" class="md-header-anchor"></a><span>Beta Reduktion</span></h3><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation" style=""><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">( <span class="cm-def">f</span> <span class="cm-operator">=&gt;</span> <span class="cm-def">x</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">f</span>(<span class="cm-variable-2">x</span>) ) (<span class="cm-variable">id</span>) (<span class="cm-number">1</span>)</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">(<span class="cm-tab" role="presentation" cm-text="	">   </span> &nbsp; <span class="cm-def">x</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable">id</span>(<span class="cm-variable-2">x</span>))<span class="cm-tab" role="presentation" cm-text="	">  </span><span class="cm-tab" role="presentation" cm-text="	">    </span>(<span class="cm-number">1</span>)</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">(<span class="cm-tab" role="presentation" cm-text="	">   </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-variable">id</span>(<span class="cm-number">1</span>))</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">(<span class="cm-def">x</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">x</span>) (<span class="cm-number">1</span>)</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-number">1</span></span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 88px;"></div><div class="CodeMirror-gutters" style="display: none; height: 88px;"></div></div></div></pre><h3><a name="eta-reduktion" class="md-header-anchor"></a><span>Eta Reduktion</span></h3><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-variable">x</span> <span class="cm-operator">=&gt;</span> <span class="cm-def">y</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable">plus</span> (<span class="cm-variable">x</span>) (<span class="cm-variable-2">y</span>)</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-variable">x</span> <span class="cm-operator">=&gt;</span> <span class="cm-tab" role="presentation" cm-text="	">   </span> &nbsp;<span class="cm-variable">plus</span> (<span class="cm-variable">x</span>)</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span> &nbsp;<span class="cm-variable">plus</span></span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 53px;"></div><div class="CodeMirror-gutters" style="display: none; height: 53px;"></div></div></div></pre><h3><a name="examples" class="md-header-anchor"></a><span>Examples</span></h3><p><code>F3</code><span> is a proper eta reduction of </span><code>F2</code></p><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation" style=""><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">id</span> <span class="cm-operator">=</span> <span class="cm-def">x</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">x</span>;</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">konst</span> <span class="cm-operator">=</span> <span class="cm-def">x</span> <span class="cm-operator">=&gt;</span> <span class="cm-def">y</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">x</span>;</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span cm-text="">​</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">F1</span> <span class="cm-operator">=</span> <span class="cm-def">x</span> <span class="cm-operator">=&gt;</span> <span class="cm-def">y</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable">konst</span> (<span class="cm-variable">id</span>) (<span class="cm-variable-2">x</span>) (<span class="cm-variable-2">y</span>);</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">F2</span> <span class="cm-operator">=</span> <span class="cm-def">x</span> <span class="cm-operator">=&gt;</span> &nbsp; &nbsp; &nbsp;<span class="cm-variable">konst</span> (<span class="cm-variable">id</span>) (<span class="cm-variable-2">x</span>);</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">F3</span> <span class="cm-operator">=</span> <span class="cm-tab" role="presentation" cm-text="	"> </span> &nbsp; &nbsp; &nbsp; &nbsp; <span class="cm-variable">konst</span> (<span class="cm-variable">id</span>);</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 106px;"></div><div class="CodeMirror-gutters" style="display: none; height: 106px;"></div></div></div></pre><p><code>a1</code><span> is a proper beta expansion of </span><code>a2</code></p><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">id</span> <span class="cm-operator">=</span> <span class="cm-def">x</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">x</span>;</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span cm-text="">​</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">a1</span> <span class="cm-operator">=</span> <span class="cm-def">y</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable">id</span>(<span class="cm-variable-2">y</span>);</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">a2</span> <span class="cm-operator">=</span> <span class="cm-def">y</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">y</span>;</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 70px;"></div><div class="CodeMirror-gutters" style="display: none; height: 70px;"></div></div></div></pre><p><code>a2</code><span> is a proper beta reduction of </span><code>a1</code></p><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">id</span> <span class="cm-operator">=</span> <span class="cm-def">x</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">x</span>;</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span cm-text="">​</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">a1</span> <span class="cm-operator">=</span> <span class="cm-def">y</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable">id</span>(<span class="cm-variable-2">y</span>);</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">a2</span> <span class="cm-operator">=</span> <span class="cm-def">y</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">y</span>;</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 70px;"></div><div class="CodeMirror-gutters" style="display: none; height: 70px;"></div></div></div></pre><p><code>id1</code><span> and </span><code>id2</code><span> are alpha-equivalent</span></p><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">id1</span> <span class="cm-operator">=</span> <span class="cm-def">x</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">x</span>;</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">id2</span> <span class="cm-operator">=</span> <span class="cm-def">y</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">y</span>;</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 35px;"></div><div class="CodeMirror-gutters" style="display: none; height: 35px;"></div></div></div></pre><p>&nbsp;</p><h2><a name="3-algebraic-data-types" class="md-header-anchor"></a><span>3. Algebraic Data Types</span></h2><blockquote><p><span>&quot;I recommend that you write programs as though JavaScript had been designed correctly.&quot;</span></p><ul><li><span>Douglas Crockford, How JavaScript works, p. 6.2</span></li></ul></blockquote><h3><a name="atomic-lamda-terms" class="md-header-anchor"></a><span>Atomic Lamda Terms</span></h3><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation" style=""><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-comment">// atoms</span></span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">id</span> <span class="cm-operator">=</span> <span class="cm-def">x</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">x</span>;</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">konst</span> <span class="cm-operator">=</span> <span class="cm-def">x</span> <span class="cm-operator">=&gt;</span> <span class="cm-def">y</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">x</span>;</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span cm-text="">​</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-comment">// derived true, false, and, or, equals, …</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">F</span> <span class="cm-operator">=</span> <span class="cm-variable">…</span>;</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">T</span> <span class="cm-operator">=</span> <span class="cm-variable">…</span>;</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 123px;"></div><div class="CodeMirror-gutters" style="display: none; height: 123px;"></div></div></div></pre><h3><a name="pair-product-type" class="md-header-anchor"></a><span>Pair, Product Type</span></h3><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">pair</span> <span class="cm-operator">=</span> <span class="cm-def">x</span> <span class="cm-operator">=&gt;</span> <span class="cm-def">y</span> <span class="cm-operator">=&gt;</span> <span class="cm-def">f</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">f</span>(<span class="cm-variable-2">x</span>)(<span class="cm-variable-2">y</span>);</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">fst</span> <span class="cm-operator">=</span> <span class="cm-def">p</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">p</span>(<span class="cm-variable">T</span>);</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">snd</span> <span class="cm-operator">=</span> <span class="cm-def">p</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">p</span>(<span class="cm-variable">F</span>);</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 53px;"></div><div class="CodeMirror-gutters" style="display: none; height: 53px;"></div></div></div></pre><h3><a name="pair-encoding" class="md-header-anchor"></a><span>Pair encoding</span></h3><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation" style=""><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">person</span> <span class="cm-operator">=</span></span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-def">firstname</span> <span class="cm-operator">=&gt;</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-def">lastname</span> <span class="cm-operator">=&gt;</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-def">age</span> <span class="cm-operator">=&gt;</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-variable">pair</span> (<span class="cm-variable">pair</span>(<span class="cm-variable-2">firstname</span>)(<span class="cm-variable-2">lastname</span>)) (<span class="cm-variable-2">age</span>);</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span cm-text="">​</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">firstn</span> <span class="cm-operator">=</span> <span class="cm-def">p</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable">fst</span>(<span class="cm-variable">fst</span>(<span class="cm-variable-2">p</span>));</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">lastn</span> &nbsp;<span class="cm-operator">=</span> <span class="cm-def">p</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable">snd</span>(<span class="cm-variable">fst</span>(<span class="cm-variable-2">p</span>));</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">age</span> &nbsp; &nbsp;<span class="cm-operator">=</span> <span class="cm-def">p</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable">snd</span>(<span class="cm-variable-2">p</span>);</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 158px;"></div><div class="CodeMirror-gutters" style="display: none; height: 158px;"></div></div></div></pre><h3><a name="either-co-product-sum" class="md-header-anchor"></a><span>Either, Co-Product, Sum</span></h3><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation" style=""><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-comment">// dual of the product</span></span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">pair</span> <span class="cm-operator">=</span> <span class="cm-def">x</span> <span class="cm-operator">=&gt;</span> <span class="cm-def">y</span> <span class="cm-operator">=&gt;</span> <span class="cm-def">f</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">f</span>(<span class="cm-variable-2">x</span>)(<span class="cm-variable-2">y</span>); <span class="cm-tab" role="presentation" cm-text="	">   </span><span class="cm-comment">// one ctor</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">fst</span> &nbsp;<span class="cm-operator">=</span> <span class="cm-def">p</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">p</span>(<span class="cm-variable">T</span>); <span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span> <span class="cm-tab" role="presentation" cm-text="	">   </span><span class="cm-comment">// accessor 1</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">snd</span> &nbsp;<span class="cm-operator">=</span> <span class="cm-def">p</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">p</span>(<span class="cm-variable">F</span>); &nbsp; &nbsp;  <span class="cm-tab" role="presentation" cm-text="	">   </span><span class="cm-tab" role="presentation" cm-text="	">    </span> <span class="cm-tab" role="presentation" cm-text="	">   </span><span class="cm-comment">// accessor 2</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span cm-text="">​</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-comment">// here we have now the basic sum type</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">Left</span> &nbsp; <span class="cm-operator">=</span> <span class="cm-def">x</span> <span class="cm-operator">=&gt;</span> <span class="cm-def">f</span> <span class="cm-operator">=&gt;</span> <span class="cm-def">g</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">f</span>(<span class="cm-variable-2">x</span>); <span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-comment">// ctor 1</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">Right</span> &nbsp;<span class="cm-operator">=</span> <span class="cm-def">x</span> <span class="cm-operator">=&gt;</span> <span class="cm-def">f</span> <span class="cm-operator">=&gt;</span> <span class="cm-def">g</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">g</span>(<span class="cm-variable-2">x</span>); <span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-comment">// ctor 2</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">either</span> <span class="cm-operator">=</span> <span class="cm-def">e</span> <span class="cm-operator">=&gt;</span> <span class="cm-def">f</span> <span class="cm-operator">=&gt;</span> <span class="cm-def">g</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">e</span>(<span class="cm-variable-2">f</span>)(<span class="cm-variable-2">g</span>); <span class="cm-tab" role="presentation" cm-text="	"> </span><span class="cm-comment">// accessor</span></span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 158px;"></div><div class="CodeMirror-gutters" style="display: none; height: 158px;"></div></div></div></pre><h3><a name="special-case-maybe" class="md-header-anchor"></a><span>Special Case: Maybe</span></h3><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation" style=""><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-comment">// go around null / undefined</span></span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">Nothing</span> <span class="cm-operator">=</span> <span class="cm-variable">Left</span> ();</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">Just</span> <span class="cm-tab" role="presentation" cm-text="	"> </span> &nbsp;<span class="cm-operator">=</span> <span class="cm-variable">Right</span>;</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">maybe</span> &nbsp; <span class="cm-operator">=</span> <span class="cm-variable">either</span>;</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span cm-text="">​</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-variable">maybe</span> (<span class="cm-variable">expressionThatMightGoWrong</span>)</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span>  (<span class="cm-variable">handleBad</span>)</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span>  (<span class="cm-variable">handleGood</span>);</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 141px;"></div><div class="CodeMirror-gutters" style="display: none; height: 141px;"></div></div></div></pre><h3><a name="example-n58" class="md-header-anchor"></a><span>Example</span></h3><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-comment">// error handling with either</span></span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">eShow</span> <span class="cm-operator">=</span> <span class="cm-def">result</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">result</span> (<span class="cm-def">msg</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">msg</span>) (<span class="cm-def">val</span> <span class="cm-operator">=&gt;</span> <span class="cm-string">"Result is:"</span> <span class="cm-operator">+</span> <span class="cm-variable-2">val</span>);</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 35px;"></div><div class="CodeMirror-gutters" style="display: none; height: 35px;"></div></div></div></pre><p>&nbsp;</p><h2><a name="4-map-filter-reduce" class="md-header-anchor"></a><span>4. Map, Filter, Reduce</span></h2><blockquote><p><span>&quot;Developers seem to love those languages most, in which they understood the value of higher-order functions.&quot;</span></p><ul><li><span>@ProfDKoenig</span></li></ul></blockquote><h3><a name="map" class="md-header-anchor"></a><span>Map</span></h3><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation" style=""><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">times</span> <span class="cm-operator">=</span> <span class="cm-def">a</span> <span class="cm-operator">=&gt;</span> <span class="cm-def">b</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">a</span> <span class="cm-operator">*</span> <span class="cm-variable-2">b</span>;</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span cm-text="">​</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">twoTimes</span> <span class="cm-operator">=</span> <span class="cm-variable">times</span>(<span class="cm-number">2</span>);</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span cm-text="">​</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">[<span class="cm-number">1</span>, <span class="cm-number">2</span>, <span class="cm-number">3</span>].<span class="cm-property">map</span>(<span class="cm-def">x</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable">times</span>(<span class="cm-number">2</span>)(<span class="cm-variable-2">x</span>));</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">[<span class="cm-number">1</span>, <span class="cm-number">2</span>, <span class="cm-number">3</span>].<span class="cm-property">map</span>(<span class="cm-variable">times</span>(<span class="cm-number">2</span>));</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">[<span class="cm-number">1</span>, <span class="cm-number">2</span>, <span class="cm-number">3</span>].<span class="cm-property">map</span>(<span class="cm-variable">twoTimes</span>);</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 123px;"></div><div class="CodeMirror-gutters" style="display: none; height: 123px;"></div></div></div></pre><h3><a name="filter" class="md-header-anchor"></a><span>Filter</span></h3><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation" style=""><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">odd</span> <span class="cm-operator">=</span> <span class="cm-def">x</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">x</span> <span class="cm-operator">%</span> <span class="cm-number">2</span> <span class="cm-operator">===</span> <span class="cm-number">1</span>;</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span cm-text="">​</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">[<span class="cm-number">1</span>, <span class="cm-number">2</span>, <span class="cm-number">3</span>].<span class="cm-property">filter</span>(<span class="cm-def">x</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">x</span> <span class="cm-operator">%</span> <span class="cm-number">2</span> <span class="cm-operator">===</span> <span class="cm-number">1</span>);</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">[<span class="cm-number">1</span>, <span class="cm-number">2</span>, <span class="cm-number">3</span>].<span class="cm-property">filter</span>(<span class="cm-def">x</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable">odd</span>(<span class="cm-variable-2">x</span>));</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">[<span class="cm-number">1</span>, <span class="cm-number">2</span>, <span class="cm-number">3</span>].<span class="cm-property">filter</span>(<span class="cm-variable">odd</span>);</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 88px;"></div><div class="CodeMirror-gutters" style="display: none; height: 88px;"></div></div></div></pre><h3><a name="reduce" class="md-header-anchor"></a><span>Reduce</span></h3><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation" style=""><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">plus</span> <span class="cm-operator">=</span> (<span class="cm-def">accu</span>, <span class="cm-def">cur</span>) <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">accu</span> <span class="cm-operator">+</span> <span class="cm-variable-2">cur</span>;</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span cm-text="">​</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">[<span class="cm-number">1</span>, <span class="cm-number">2</span>, <span class="cm-number">3</span>].<span class="cm-property">reduce</span>((<span class="cm-def">accu</span>, <span class="cm-def">cur</span>) <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">accu</span> <span class="cm-operator">+</span> <span class="cm-variable-2">cur</span>);</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">[<span class="cm-number">1</span>, <span class="cm-number">2</span>, <span class="cm-number">3</span>].<span class="cm-property">reduce</span>(<span class="cm-variable">plus</span>);</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span cm-text="">​</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-comment">// variant with initial accu value as 2nd argument</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-comment">// then cur starts at first element</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">[<span class="cm-number">1</span>, <span class="cm-number">2</span>, <span class="cm-number">3</span>].<span class="cm-property">reduce</span>(<span class="cm-variable">plus</span>, <span class="cm-number">0</span>);</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 141px;"></div><div class="CodeMirror-gutters" style="display: none; height: 141px;"></div></div></div></pre><h3><a name="examples-n73" class="md-header-anchor"></a><span>Examples</span></h3><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-comment">// function that checks which numbers in an array are divideable </span></span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-comment">// by the given argument</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">divides</span> <span class="cm-operator">=</span> <span class="cm-def">x</span> <span class="cm-operator">=&gt;</span> <span class="cm-def">y</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">y</span> <span class="cm-operator">%</span> <span class="cm-variable-2">x</span> <span class="cm-operator">===</span> <span class="cm-number">0</span>;</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 53px;"></div><div class="CodeMirror-gutters" style="display: none; height: 53px;"></div></div></div></pre><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-comment">// function that joins values of an array together with given argument</span></span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">join</span> <span class="cm-operator">=</span> (<span class="cm-def">a</span>) <span class="cm-operator">=&gt;</span> (<span class="cm-def">b</span>, <span class="cm-def">c</span>) <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">b</span> <span class="cm-operator">+</span> <span class="cm-variable-2">a</span> <span class="cm-operator">+</span> <span class="cm-variable-2">c</span>;</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 35px;"></div><div class="CodeMirror-gutters" style="display: none; height: 35px;"></div></div></div></pre><p>&nbsp;</p><h2><a name="5-scripting-pwa-plotter-excel" class="md-header-anchor"></a><span>5. Scripting, PWA, Plotter, Excel</span></h2><blockquote><p><span>&quot;Unfortunately, JS has a misfeature called Automated Semicolon Insertion. It can fail in bad ways, so write like a professional.&quot;</span></p><ul><li><span>Douglas Crockford, &quot;How JavaScript works.&quot;</span></li></ul></blockquote><h3><a name="why-scripting" class="md-header-anchor"></a><span>Why Scripting?</span></h3><ul><li><span>Command Line</span></li><li><span>Automation</span></li><li><span>Build System</span></li><li><span>Templating</span></li><li><span>Code Distribution</span></li><li><span>Formulae</span></li><li><span>Business Rules</span></li><li><span>Smart Configuration</span></li><li><span>Product Lines</span></li><li><span>DSL</span></li><li><span>Self Modifying Code</span></li><li><span>...</span></li></ul><h3><a name="progressive-web-app" class="md-header-anchor"></a><span>Progressive Web App</span></h3><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-variable">document</span>.<span class="cm-property">write</span>(<span class="cm-string">'&lt;script src=...'</span>);</span></pre></div></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 18px;"></div><div class="CodeMirror-gutters" style="display: none; height: 18px;"></div></div></div></pre><h3><a name="function-plotter-eval" class="md-header-anchor"></a><span>Function Plotter: eval</span></h3><p><span>Works as if the code was copied verbatim in the place of the eval. =&gt; You share the scope.</span></p><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-variable">eval</span>(<span class="cm-string">'some code'</span>);</span></pre></div></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 18px;"></div><div class="CodeMirror-gutters" style="display: none; height: 18px;"></div></div></div></pre><h3><a name="function-plotter-function" class="md-header-anchor"></a><span>Function Plotter: Function()</span></h3><p><code>Function()</code><span> is like </span><code>eval()</code><span> but declares parameters and executes in the global scope. It creates a reference.</span></p><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">add</span> <span class="cm-operator">=</span> <span class="cm-variable">Function</span>(<span class="cm-string">'x'</span>, <span class="cm-string">'y'</span>, <span class="cm-string">'return x+y'</span>);</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-variable">add</span>(<span class="cm-number">1</span>, <span class="cm-number">2</span>);</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-variable">add</span>(<span class="cm-number">2</span>, <span class="cm-number">3</span>); <span class="cm-comment">// no need to re-parse</span></span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 53px;"></div><div class="CodeMirror-gutters" style="display: none; height: 53px;"></div></div></div></pre><p>&nbsp;</p><h3><a name="scripting-caution" class="md-header-anchor"></a><span>Scripting Caution</span></h3><p><span>In JavaScript you cannot exclude possibly harmful side effects from scripts that are loaded from foreign sources...</span></p><p><span>=&gt; Privacy, Security, Stability</span></p><h3><a name="examples-n121" class="md-header-anchor"></a><span>Examples</span></h3><p><span>Calculate the bonus with given attributes:</span></p><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">bonusCalculation</span> <span class="cm-operator">=</span> <span class="cm-def">x</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">x</span>.<span class="cm-property">bonus</span> <span class="cm-operator">=</span> <span class="cm-variable">eval</span>(<span class="cm-variable-2">x</span>.<span class="cm-property">revenue</span>) <span class="cm-operator">*</span> <span class="cm-variable">factor_</span>;</span></pre></div></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 18px;"></div><div class="CodeMirror-gutters" style="display: none; height: 18px;"></div></div></div></pre><p><span>Calculate the bonus with given attributes using Function():</span></p><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">bonusCalculation</span> <span class="cm-operator">=</span> <span class="cm-variable">Function</span>(<span class="cm-string">'x'</span>, <span class="cm-string">'return x.bonus = x.revenue *'</span> <span class="cm-operator">+</span> <span class="cm-variable">factor_</span>);</span></pre></div></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 18px;"></div><div class="CodeMirror-gutters" style="display: none; height: 18px;"></div></div></div></pre><p>&nbsp;</p><h2><a name="6-objects" class="md-header-anchor"></a><span>6. Objects</span></h2><blockquote><p><span>&quot;It&#39;s called object-oriented to tell you what you should do with it: object!&quot;</span></p><ul><li><span>Phil Wadler, quoted from memory</span></li></ul></blockquote><h3><a name="open--dynamic" class="md-header-anchor"></a><span>Open &amp; dynamic</span></h3><p><span>JS &quot;Objects&quot;.</span></p><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation" style=""><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">good</span> <span class="cm-operator">=</span> {</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-property">firstname</span> : <span class="cm-string">"Good"</span>,</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-property">lastname</span> : <span class="cm-string">"Boy"</span>,</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-property">getName</span> : <span class="cm-keyword">function</span>() {</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-keyword">return</span> <span class="cm-keyword">this</span>.<span class="cm-property">firstname</span> <span class="cm-operator">+</span> <span class="cm-string">" "</span> <span class="cm-operator">+</span> <span class="cm-keyword">this</span>.<span class="cm-property">lastname</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span>}</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">};</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-comment">// no safety but super dynamic</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-comment">// unobvious how to share structure</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-comment">// beware of "this"! See Adam Breindl last week.</span></span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 176px;"></div><div class="CodeMirror-gutters" style="display: none; height: 176px;"></div></div></div></pre><h3><a name="closed--explicit" class="md-header-anchor"></a><span>Closed &amp; explicit</span></h3><p><span>Closure scope, no &quot;this&quot;.</span></p><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation" style=""><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">function</span> <span class="cm-def">Person</span>(<span class="cm-def">first</span>, <span class="cm-def">last</span>) {</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-keyword">let</span> <span class="cm-def">firstname</span> <span class="cm-operator">=</span> <span class="cm-variable-2">first</span>; <span class="cm-comment">// optional</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-keyword">let</span> <span class="cm-def">lastname</span> <span class="cm-operator">=</span> <span class="cm-variable-2">last</span>;</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-keyword">return</span> {</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-property">getName</span>: <span class="cm-keyword">function</span>() {</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-keyword">return</span> <span class="cm-variable-2">firstname</span> <span class="cm-operator">+</span> <span class="cm-string">" "</span> <span class="cm-operator">+</span> <span class="cm-variable-2">lastname</span> }</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span>}</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span>}</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">}</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-comment">// best safety, easy to share structure, but no class</span></span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 176px;"></div><div class="CodeMirror-gutters" style="display: none; height: 176px;"></div></div></div></pre><h3><a name="mixed--classified" class="md-header-anchor"></a><span>Mixed &amp; classified</span></h3><p><span>Depends on &quot;new&quot;. Is the &quot;default&quot; construction.</span></p><p><span>Still dynamic but all &quot;instances&quot; can be changed at once by changing the prototype!</span></p><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation" style=""><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">Person</span> <span class="cm-operator">=</span> ( () <span class="cm-operator">=&gt;</span> { <span class="cm-comment">// lexical scope</span></span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-keyword">function</span> <span class="cm-def">Person</span>(<span class="cm-def">first</span>, <span class="cm-def">last</span>) { <span class="cm-comment">// ctor, binding</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-keyword">this</span>.<span class="cm-property">firstname</span> <span class="cm-operator">=</span> <span class="cm-variable-2">first</span>;</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-keyword">this</span>.<span class="cm-property">lastname</span> <span class="cm-operator">=</span> <span class="cm-variable-2">last</span>;</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span>}</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-variable-2">Person</span>.<span class="cm-property">prototype</span>.<span class="cm-property">getName</span> <span class="cm-operator">=</span> <span class="cm-keyword">function</span>() {</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-keyword">return</span> <span class="cm-keyword">this</span>.<span class="cm-property">firstname</span> <span class="cm-operator">+</span> <span class="cm-string">" "</span> <span class="cm-operator">+</span> <span class="cm-keyword">this</span>.<span class="cm-property">lastname</span>;</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span>};</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-keyword">return</span> <span class="cm-variable-2">Person</span>;</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">}) (); <span class="cm-comment">// IIFE</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-comment">// new Person("Good", "Boy") instanceof Person</span></span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 194px;"></div><div class="CodeMirror-gutters" style="display: none; height: 194px;"></div></div></div></pre><h3><a name="example-n143" class="md-header-anchor"></a><span>Example</span></h3><p><span>Check wether two Arrays are equal:</span></p><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation" style=""><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-variable">Array</span>.<span class="cm-property">prototype</span>.<span class="cm-property">eq</span> <span class="cm-operator">=</span> <span class="cm-keyword">function</span>(<span class="cm-def">array</span>) {</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> &nbsp; &nbsp;<span class="cm-keyword">if</span> (<span class="cm-keyword">this</span>.<span class="cm-property">length</span> <span class="cm-operator">!==</span> <span class="cm-variable-2">array</span>.<span class="cm-property">length</span>) <span class="cm-keyword">return</span> <span class="cm-atom">false</span>;</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> &nbsp; &nbsp;<span class="cm-keyword">for</span> (<span class="cm-keyword">let</span> <span class="cm-def">i</span> <span class="cm-operator">=</span> <span class="cm-number">0</span>; <span class="cm-variable-2">i</span> <span class="cm-operator">&lt;</span> <span class="cm-variable-2">array</span>.<span class="cm-property">length</span>; <span class="cm-variable-2">i</span><span class="cm-operator">++</span>) {</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> &nbsp; &nbsp; &nbsp; &nbsp;<span class="cm-keyword">if</span> (<span class="cm-keyword">this</span>[<span class="cm-variable-2">i</span>] <span class="cm-operator">!==</span> <span class="cm-variable-2">array</span>[<span class="cm-variable-2">i</span>]) <span class="cm-keyword">return</span> <span class="cm-atom">false</span>;</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> &nbsp;  }</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> &nbsp; &nbsp;<span class="cm-keyword">return</span> <span class="cm-atom">true</span>;</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">}</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 123px;"></div><div class="CodeMirror-gutters" style="display: none; height: 123px;"></div></div></div></pre><p>&nbsp;</p><h2><a name="7-classes" class="md-header-anchor"></a><span>7. Classes</span></h2><blockquote><p><span>&quot;Classes tend to be bad modules.&quot;</span></p><ul><li><span>D. Crockford, How JS works, p. 17.0</span></li></ul></blockquote><h3><a name="class-keyword" class="md-header-anchor"></a><code>class</code><span> Keyword</span></h3><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation" style=""><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">class</span> <span class="cm-def">Person</span> {</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-property">constructor</span>(<span class="cm-def">first</span>, <span class="cm-def">last</span>) {</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-keyword">this</span>.<span class="cm-property">firstname</span> <span class="cm-operator">=</span> <span class="cm-variable-2">first</span>;</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-keyword">this</span>.<span class="cm-property">lastname</span> <span class="cm-operator">=</span> <span class="cm-variable-2">last</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span>}</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-property">getName</span>() {</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-keyword">return</span> <span class="cm-keyword">this</span>.<span class="cm-property">firstname</span> <span class="cm-operator">+</span> <span class="cm-string">" "</span> <span class="cm-operator">+</span> <span class="cm-keyword">this</span>.<span class="cm-property">lastname</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span>}</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">}</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-comment">// new Person("Good", "Boy") instanceof Person</span></span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 176px;"></div><div class="CodeMirror-gutters" style="display: none; height: 176px;"></div></div></div></pre><h3><a name="extends-keyword" class="md-header-anchor"></a><code>extends</code><span> Keyword</span></h3><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation" style=""><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">class</span> <span class="cm-def">Student</span> <span class="cm-keyword">extends</span> <span class="cm-variable">Person</span> {</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-property">constructor</span> (<span class="cm-def">first</span>, <span class="cm-def">last</span>, <span class="cm-def">grade</span>) {</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-keyword">super</span>(<span class="cm-variable-2">first</span>, <span class="cm-variable-2">last</span>); <span class="cm-comment">// never forget</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-keyword">this</span>.<span class="cm-property">grade</span> <span class="cm-operator">=</span> <span class="cm-variable-2">grade</span>;</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span>}</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">}</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">s</span> <span class="cm-operator">=</span> <span class="cm-keyword">new</span> <span class="cm-variable">Student</span>(<span class="cm-string">"Top"</span>,<span class="cm-string">"Student"</span>, <span class="cm-number">5.5</span>);</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 123px;"></div><div class="CodeMirror-gutters" style="display: none; height: 123px;"></div></div></div></pre><h3><a name="prototype-chain" class="md-header-anchor"></a><span>Prototype chain</span></h3><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">s</span> <span class="cm-operator">=</span> <span class="cm-keyword">new</span> <span class="cm-variable">Student</span>()</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-comment">// s.__proto__ === Student.prototype;</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-comment">// Object.getPrototypeOf(s) === Student.prototype;</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-comment">// =&gt; s instanceof Student</span></span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 70px;"></div><div class="CodeMirror-gutters" style="display: none; height: 70px;"></div></div></div></pre><h3><a name="example-n159" class="md-header-anchor"></a><span>Example</span></h3><p><span>Function composition -&gt; it must work for all functions!</span></p><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation" style=""><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-variable">Function</span>.<span class="cm-property">prototype</span>.<span class="cm-property">then</span> <span class="cm-operator">=</span> <span class="cm-keyword">function</span>(<span class="cm-def">bracketFunc</span>) {</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> &nbsp; &nbsp;<span class="cm-comment">// this(number -&gt; result of the first function </span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> &nbsp; &nbsp;<span class="cm-comment">// with the value at the end f.e. ..(1))</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> &nbsp; &nbsp;<span class="cm-keyword">const</span> <span class="cm-def">compose</span> <span class="cm-operator">=</span> <span class="cm-def">bracketFunc</span> <span class="cm-operator">=&gt;</span> <span class="cm-def">number</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">bracketFunc</span>( <span class="cm-keyword">this</span>(<span class="cm-variable-2">number</span>) );</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> &nbsp; &nbsp;<span class="cm-keyword">return</span> <span class="cm-variable-2">compose</span>(<span class="cm-variable-2">bracketFunc</span>);</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">}</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 106px;"></div><div class="CodeMirror-gutters" style="display: none; height: 106px;"></div></div></div></pre><p>&nbsp;</p><h2><a name="8-moves-user-interfaces" class="md-header-anchor"></a><span>8. Moves, User Interfaces</span></h2><blockquote><p><span>&quot;Live&#39;s a dance you learn as you go. Sometimes you lead, sometimes you follow.&quot;</span></p><ul><li><span>John Michael Montgomery</span></li></ul></blockquote><h3><a name="compare-with-dancing" class="md-header-anchor"></a><span>Compare with Dancing</span></h3><ol start='' ><li><span>You must learn the moves.</span></li><li><span>Then you can combine the moves and adapt to the situation at hand.</span></li></ol><h3><a name="recognize-moves" class="md-header-anchor"></a><span>Recognize Moves</span></h3><ul><li><span>Become aware what you do.</span></li><li><span>We program collaboratively and look for moves.</span></li></ul><h3><a name="task-1-improve-the-tests" class="md-header-anchor"></a><span>Task 1: Improve the Tests</span></h3><ul><li><span>More structure.</span></li><li><span>Better reports when tests fail.</span></li><li><span>smooth transition.</span></li></ul><h3><a name="task-2-todo-list-example" class="md-header-anchor"></a><span>Task 2: Todo List Example</span></h3><ul><li><span>What is the expected result?</span></li><li><span>What is the simplest thing that could possibly work?</span></li></ul><h3><a name="moves---your-choice" class="md-header-anchor"></a><span>Moves - Your Choice</span></h3><h4><a name="0-explore" class="md-header-anchor"></a><span>0: Explore</span></h4><ul><li><span>Technical feasibility, hypotheses, border cases.</span></li><li><span>The goal is to learn and verify, delete when finished.</span></li><li><span>Give yourself a timebox.</span></li></ul><h4><a name="1-start-at-the-end" class="md-header-anchor"></a><span>1: Start at the End</span></h4><ul><li><span>Make static &quot;sketch&quot; of the result before adding dynamic features.</span></li><li><span>Dynamic sketches: all JS, CSS in a single HTML file.</span></li></ul><h4><a name="2-extract" class="md-header-anchor"></a><span>2: Extract</span></h4><ul><li><span>Replace static values with variables.</span></li><li><span>Replace repetitions with mappings and loops.</span></li></ul><h4><a name="3-abstract" class="md-header-anchor"></a><span>3: Abstract</span></h4><ul><li><span>Discover the concept behind what you have extracted. Give it a name.</span></li><li><span>It should work for itself and in combination.</span></li><li><span>Revert if you cannot find one.</span></li></ul><h4><a name="4-reorganize" class="md-header-anchor"></a><span>4: Reorganize</span></h4><ul><li><span>Organize and re-factor to make your future work easier.</span></li><li><span>Facilitate extensions or improvements.</span></li><li><span>Prepare for release.</span></li></ul><h4><a name="5-release" class="md-header-anchor"></a><span>5: Release</span></h4><ul><li><span>The solution must stand on its own without tacit knowledge or external help.</span></li><li><span>Tests, documentation, examples.</span></li><li><span>Before every push to the Repository.</span></li></ul><h4><a name="6-retrospective" class="md-header-anchor"></a><span>6: Retrospective</span></h4><ul><li><span>What to keep?</span></li><li><span>What to try differently next time?</span></li></ul><h3><a name="observations" class="md-header-anchor"></a><span>Observations</span></h3><ul><li><span>Balance &amp; distance</span></li><li><span>Which technologies support my moves: dynamic exploration, refactoring</span></li><li><span>Per feature, per project, whole career, ...</span></li></ul><h3><a name="example-n254" class="md-header-anchor"></a><span>Example</span></h3><p><span>Failsafe callback:</span></p><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">failSafe</span> <span class="cm-operator">=</span> <span class="cm-def">defaultValue</span> <span class="cm-operator">=&gt;</span> <span class="cm-def">callback</span> <span class="cm-operator">=&gt;</span> <span class="cm-def">argToCallback</span> <span class="cm-operator">=&gt;</span> {</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> &nbsp; &nbsp;<span class="cm-keyword">return</span> <span class="cm-variable-2">argToCallback</span> <span class="cm-operator">===</span> <span class="cm-atom">null</span> <span class="cm-operator">?</span> <span class="cm-variable-2">defaultValue</span> : <span class="cm-variable-2">callback</span>(<span class="cm-variable-2">argToCallback</span>);</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">}</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 53px;"></div><div class="CodeMirror-gutters" style="display: none; height: 53px;"></div></div></div></pre><p>&nbsp;</p><h2><a name="9-ui-engineering-mvc" class="md-header-anchor"></a><span>9. UI Engineering, MVC</span></h2><blockquote><p><span>&quot;Frameworks and APIs change fast. Software design principles are evergreen. Learn principles that translate across language barriers.&quot;</span></p><ul><li><span>Eric Elliot</span></li></ul></blockquote><h3><a name="callback---hof" class="md-header-anchor"></a><span>Callback - HOF</span></h3><p><span>Higher-order Function.</span></p><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation" style=""><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">function</span> <span class="cm-def">test</span>(<span class="cm-def">name</span>, <span class="cm-def">callback</span>) {</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-keyword">const</span> <span class="cm-def">assert</span> <span class="cm-operator">=</span> <span class="cm-variable">Assert</span>();<span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-comment">// prework</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-variable-2">callback</span>(<span class="cm-variable-2">assert</span>);<span class="cm-tab" role="presentation" cm-text="	">   </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-comment">// callback</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-variable">report</span>(<span class="cm-variable-2">name</span>, <span class="cm-variable-2">assert</span>.<span class="cm-property">getOk</span>());<span class="cm-tab" role="presentation" cm-text="	">   </span><span class="cm-comment">// postwork</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">}</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 88px;"></div><div class="CodeMirror-gutters" style="display: none; height: 88px;"></div></div></div></pre><h3><a name="observable" class="md-header-anchor"></a><span>Observable</span></h3><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation" style=""><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">Observable</span> <span class="cm-operator">=</span> <span class="cm-def">value</span> <span class="cm-operator">=&gt;</span> {</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-keyword">const</span> <span class="cm-def">listeners</span> <span class="cm-operator">=</span> []; <span class="cm-comment">// many</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-keyword">return</span> {</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-property">onChange</span>: <span class="cm-def">callback</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">listeners</span>.<span class="cm-property">push</span>(<span class="cm-variable-2">callback</span>),</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-property">getValue</span>: () <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">value</span>,</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-property">setValue</span>: <span class="cm-def">val</span> <span class="cm-operator">=&gt;</span> {</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-keyword">if</span> (<span class="cm-variable-2">value</span> <span class="cm-operator">===</span> <span class="cm-variable-2">val</span>) <span class="cm-keyword">return</span>; <span class="cm-comment">// protection</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-comment">// ordering</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;<span class="cm-variable-2">value</span> <span class="cm-operator">=</span> <span class="cm-variable-2">val</span>;</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-variable-2">listeners</span>.<span class="cm-property">forEach</span>(<span class="cm-def">notify</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">notify</span>(<span class="cm-variable-2">val</span>));</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span>}</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span>}</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">};</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 229px;"></div><div class="CodeMirror-gutters" style="display: none; height: 229px;"></div></div></div></pre><h3><a name="mvc" class="md-header-anchor"></a><span>MVC</span></h3><p><img src="mvc.PNG" referrerpolicy="no-referrer" alt="MVC Bild"></p><h3><a name="example-n271" class="md-header-anchor"></a><span>Example</span></h3><p><span>Using Observable that it keeps track of the sum of all values:</span></p><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-variable">trackable</span>.<span class="cm-property">onChange</span>( <span class="cm-def">_</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable">sum</span> <span class="cm-operator">+=</span> <span class="cm-variable">trackable</span>.<span class="cm-property">getValue</span>() );</span></pre></div></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 18px;"></div><div class="CodeMirror-gutters" style="display: none; height: 18px;"></div></div></div></pre><p>&nbsp;</p><h2><a name="10-async-programming" class="md-header-anchor"></a><span>10. Async Programming</span></h2><blockquote><p><span>&quot;Don&#39;t call us. We call you.&quot;</span></p><ul><li><span>Hollywood</span></li></ul></blockquote><h3><a name="testing" class="md-header-anchor"></a><span>Testing</span></h3><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript" style="break-inside: unset;"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation" style=""><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-variable">test</span>(<span class="cm-string">"todo-memory-leak"</span>, <span class="cm-def">assert</span> <span class="cm-operator">=&gt;</span> {</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-keyword">const</span> <span class="cm-def">todoController</span> <span class="cm-operator">=</span> <span class="cm-variable">TodoController</span>();</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span cm-text="">​</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> &nbsp; &nbsp;<span class="cm-variable-2">todoController</span>.<span class="cm-property">onTodoAdd</span>(<span class="cm-def">todo</span> <span class="cm-operator">=&gt;</span> {</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-variable-2">todoController</span>.<span class="cm-property">onTodoRemove</span>( (<span class="cm-def">todo</span>, <span class="cm-def">removeMe</span>) <span class="cm-operator">=&gt;</span> {</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-variable-2">removeMe</span>(); <span class="cm-comment">// idea: self remove</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span>});</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span>});</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span cm-text="">​</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> &nbsp; &nbsp;<span class="cm-keyword">for</span> (<span class="cm-keyword">let</span> <span class="cm-def">i</span><span class="cm-operator">=</span><span class="cm-number">0</span>; <span class="cm-variable-2">i</span><span class="cm-operator">&lt;</span><span class="cm-number">10000</span>; <span class="cm-variable-2">i</span><span class="cm-operator">++</span>){</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-keyword">const</span> <span class="cm-def">todo</span> <span class="cm-operator">=</span> <span class="cm-variable-2">todoController</span>.<span class="cm-property">addTodo</span>();</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-variable-2">todoController</span>.<span class="cm-property">removeTodo</span>(<span class="cm-variable-2">todo</span>);</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span>}</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">});</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 246px;"></div><div class="CodeMirror-gutters" style="display: none; height: 246px;"></div></div></div></pre><h3><a name="callback-events" class="md-header-anchor"></a><span>Callback, Events</span></h3><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation" style=""><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">function</span> <span class="cm-def">start</span>() {</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-comment">//...</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-variable">window</span>.<span class="cm-property">onkeydown</span> <span class="cm-operator">=</span> <span class="cm-def">evt</span> <span class="cm-operator">=&gt;</span> {</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-comment">// doSomething();</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span>};</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-variable">setInterval</span>(() <span class="cm-operator">=&gt;</span> {</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-comment">// doSomething();</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span>}, <span class="cm-number">1000</span> <span class="cm-operator">/</span> <span class="cm-number">5</span>);</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">}</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 158px;"></div><div class="CodeMirror-gutters" style="display: none; height: 158px;"></div></div></div></pre><h3><a name="promise" class="md-header-anchor"></a><span>Promise</span></h3><p><span>Most prominent use:</span></p><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-variable">fetch</span> (<span class="cm-string">'http://fhnw.ch/json/students/list'</span>)</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">.<span class="cm-property">then</span>(<span class="cm-def">response</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">response</span>.<span class="cm-property">json</span>())</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">.<span class="cm-property">then</span>(<span class="cm-def">students</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable">console</span>.<span class="cm-property">log</span>(<span class="cm-variable-2">students</span>.<span class="cm-property">length</span>))</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">.<span class="cm-property">catch</span> (<span class="cm-def">err</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable">console</span>.<span class="cm-property">log</span>(<span class="cm-variable-2">err</span>)</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 70px;"></div><div class="CodeMirror-gutters" style="display: none; height: 70px;"></div></div></div></pre><p><span>Success / Failure callbacks:</span></p><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript" style="break-inside: unset;"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation" style=""><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-comment">// definition</span></span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">processEven</span> <span class="cm-operator">=</span> <span class="cm-def">i</span> <span class="cm-operator">=&gt;</span> <span class="cm-keyword">new</span> <span class="cm-variable">Promise</span>( (<span class="cm-def">resolve</span>, <span class="cm-def">reject</span>) <span class="cm-operator">=&gt;</span> {</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-keyword">if</span> (<span class="cm-variable-2">i</span> <span class="cm-operator">%</span> <span class="cm-number">2</span> <span class="cm-operator">===</span> <span class="cm-number">0</span>) {</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-variable-2">resolve</span>(<span class="cm-variable-2">i</span>);</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span>} <span class="cm-keyword">else</span> {</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-variable-2">reject</span>(<span class="cm-variable-2">i</span>);</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span>}</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">});</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span cm-text="">​</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-comment">// use</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-variable">processEven</span>(<span class="cm-number">4</span>)</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">.<span class="cm-property">then</span> ( <span class="cm-def">it</span> <span class="cm-operator">=&gt;</span> {<span class="cm-variable">console</span>.<span class="cm-property">log</span>(<span class="cm-variable-2">it</span>); <span class="cm-keyword">return</span> <span class="cm-variable-2">it</span>} ) <span class="cm-comment">// auto promotion</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">.<span class="cm-property">then</span> ( <span class="cm-def">it</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable">processEven</span>(<span class="cm-variable-2">it</span><span class="cm-operator">+</span><span class="cm-number">1</span>))</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">.<span class="cm-property">catch</span>( <span class="cm-def">err</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable">console</span>.<span class="cm-property">log</span>( <span class="cm-string">"Error: "</span> <span class="cm-operator">+</span> <span class="cm-variable-2">err</span>))</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 246px;"></div><div class="CodeMirror-gutters" style="display: none; height: 246px;"></div></div></div></pre><h3><a name="async--await" class="md-header-anchor"></a><span>Async / Await</span></h3><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation" style=""><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">foo</span> <span class="cm-operator">=</span> <span class="cm-keyword">async</span> <span class="cm-def">i</span> <span class="cm-operator">=&gt;</span> {</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-keyword">const</span> <span class="cm-def">x</span> <span class="cm-operator">=</span> <span class="cm-keyword">await</span> <span class="cm-variable">processEven</span>(<span class="cm-variable-2">i</span>).<span class="cm-property">catch</span>( <span class="cm-def">err</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">err</span>);</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-variable">console</span>.<span class="cm-property">log</span>(<span class="cm-string">"foo: "</span> <span class="cm-operator">+</span> <span class="cm-variable-2">x</span>);</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">};</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-variable">foo</span>(<span class="cm-number">4</span>);</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 88px;"></div><div class="CodeMirror-gutters" style="display: none; height: 88px;"></div></div></div></pre><p><span>Other variant:</span></p><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation" style=""><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">async</span> <span class="cm-keyword">function</span> <span class="cm-def">foo</span>(<span class="cm-def">i</span>) {</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-keyword">try</span> {</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-keyword">const</span> <span class="cm-def">x</span> <span class="cm-operator">=</span> <span class="cm-keyword">await</span> <span class="cm-variable">processEven</span>(<span class="cm-variable-2">i</span>);</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-variable">console</span>.<span class="cm-property">log</span>(<span class="cm-string">"foo: "</span> <span class="cm-operator">+</span> <span class="cm-variable-2">x</span>);</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span>}</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-keyword">catch</span>(<span class="cm-def">err</span>) { <span class="cm-variable">console</span>.<span class="cm-property">log</span>(<span class="cm-variable-2">err</span>); }</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">};</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-variable">foo</span>(<span class="cm-number">4</span>);</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 141px;"></div><div class="CodeMirror-gutters" style="display: none; height: 141px;"></div></div></div></pre><h3><a name="example-n294" class="md-header-anchor"></a><span>Example</span></h3><p><span>A NullSafe construction in the style of a </span><code>Promise</code><span>:</span></p><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation" style=""><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">const</span> <span class="cm-def">NullSafe</span> <span class="cm-operator">=</span> <span class="cm-def">x</span> <span class="cm-operator">=&gt;</span> {</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> &nbsp; &nbsp;<span class="cm-keyword">const</span> <span class="cm-def">isNullSafe</span> <span class="cm-operator">=</span> <span class="cm-def">y</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">y</span> <span class="cm-operator">&amp;&amp;</span> <span class="cm-variable-2">y</span>.<span class="cm-property">then</span>;</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> &nbsp; &nbsp;<span class="cm-keyword">const</span> <span class="cm-def">maywrap</span> <span class="cm-operator">=</span> <span class="cm-def">y</span> <span class="cm-operator">=&gt;</span> <span class="cm-variable-2">isNullSafe</span>(<span class="cm-variable-2">y</span>) <span class="cm-operator">?</span> <span class="cm-variable-2">y</span> : <span class="cm-variable">NullSafe</span>(<span class="cm-variable-2">y</span>);</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> &nbsp; &nbsp;<span class="cm-keyword">return</span> {</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> &nbsp; &nbsp; &nbsp; &nbsp;<span class="cm-property">then</span>: <span class="cm-def">fn</span> <span class="cm-operator">=&gt;</span> (<span class="cm-variable-2">x</span> <span class="cm-operator">!==</span> <span class="cm-atom">null</span> <span class="cm-operator">&amp;&amp;</span> <span class="cm-variable-2">x</span> <span class="cm-operator">!=</span> <span class="cm-atom">undefined</span>)</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> &nbsp; &nbsp; &nbsp;  <span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-operator">?</span> <span class="cm-variable-2">maywrap</span>(<span class="cm-variable-2">fn</span>(<span class="cm-variable-2">x</span>)) </span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> &nbsp; &nbsp; &nbsp;  <span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span>: <span class="cm-variable">NullSafe</span>(<span class="cm-variable-2">x</span>)</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> &nbsp;  }</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">};</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 158px;"></div><div class="CodeMirror-gutters" style="display: none; height: 158px;"></div></div></div></pre><p>&nbsp;</p><h2><a name="11-data-flow" class="md-header-anchor"></a><span>11. Data Flow</span></h2><h3><a name="coordination-schemata" class="md-header-anchor"></a><span>Coordination schemata</span></h3><blockquote><p><span>Similar to concurrency</span></p></blockquote><ol start='' ><li><span>No coordination needed</span></li><li><span>Sequence (of side effects)</span></li><li><span>Dependeny on former results</span></li></ol><h4><a name="no-coordination" class="md-header-anchor"></a><span>No Coordination</span></h4><blockquote><p><span>Nothing to do !</span></p></blockquote><ul><li><span>Execution model: confined</span></li><li><span>All actions run independently</span></li></ul><h4><a name="sequence" class="md-header-anchor"></a><span>Sequence</span></h4><blockquote><p><span>Actor</span></p></blockquote><ul><li><span>In a sequence of actions, each action can only start if the preceding one has finished</span></li><li><span>How to achieve this =&gt; Delegated Coordination =&gt; Scheduler</span></li></ul><h4><a name="result-dependency" class="md-header-anchor"></a><span>Result Dependency</span></h4><ul><li><span>Action B and C need the result of action A</span></li><li><span>A must be executed </span><strong><span>exactly once</span></strong><span> before B and C</span></li><li><span>How to do this =&gt; Implicit Coordination =&gt; DataFlowVariable</span></li></ul><h3><a name="scheduler-idea" class="md-header-anchor"></a><span>Scheduler Idea</span></h3><ul><li><span>Queue (FIFO) of functions that are started with a lock</span></li><li><span>Callback unlocks</span></li></ul><h3><a name="dataflowvariable" class="md-header-anchor"></a><span>DataFlowVariable</span></h3><ul><li><span>Function, that sets a value if it is not already set. Returns the value.</span></li><li><span>Lazy: Access to variables that will become available later</span></li><li><span>Trick: Do not set the value, but a function that returns the value</span></li></ul><p>&nbsp;</p><h2><a name="12-modules" class="md-header-anchor"></a><span>12. Modules</span></h2><blockquote><p><span>&quot;Well-structured software is easy to write and to debug, and provides a collection of modules that can be reused to reduce future programming costs.&quot;</span></p><ul><li><span>John Hughes</span></li></ul></blockquote><h3><a name="why-modules" class="md-header-anchor"></a><span>Why Modules?</span></h3><ul><li><span>Organize the Code</span></li><li><span>Clear dependencies</span></li><li><span>Avoid errors: Globals, Scoping, Namespace</span></li></ul><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation" style=""><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-comment">// avoid something like this in your html document</span></span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-operator">&lt;</span><span class="cm-variable">script</span> <span class="cm-variable">src</span><span class="cm-operator">=</span><span class="cm-string">"fileA.js"</span><span class="cm-operator">&gt;</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-operator">&lt;</span><span class="cm-variable">script</span> <span class="cm-variable">src</span><span class="cm-operator">=</span><span class="cm-string">"fileB.js"</span><span class="cm-operator">&gt;</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-operator">&lt;</span><span class="cm-variable">script</span> <span class="cm-variable">src</span><span class="cm-operator">=</span><span class="cm-string">"fileC.js"</span><span class="cm-operator">&gt;</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-comment">// if fileA.js has a reference on fileC.js it won't work !!!</span></span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 88px;"></div><div class="CodeMirror-gutters" style="display: none; height: 88px;"></div></div></div></pre><h4><a name="distinguish" class="md-header-anchor"></a><span>Distinguish</span></h4><ul><li><span>How I want to edit the code</span></li><li><span>How I want to deliver the code</span></li></ul><h3><a name="es6-modules" class="md-header-anchor"></a><span>ES6 Modules</span></h3><p><span>They are not...</span></p><ul><li><span>Packages (those have versions)</span></li><li><span>Dependencies, Libraries, Releases</span></li><li><span>Units of publication</span></li><li><span>Objects</span></li></ul><h4><a name="package-manager" class="md-header-anchor"></a><span>Package Manager</span></h4><p><code>webpack</code><span>, </span><code>npm</code><span>, </span><code>bower</code><span>, </span><code>yarn</code><span>, ...</span></p><h4><a name="build-tools" class="md-header-anchor"></a><span>Build Tools</span></h4><p><code>webpack</code><span>, </span><code>npm</code><span>, </span><code>grunt</code><span>, </span><code>gulp</code><span>, ...</span></p><h4><a name="legacy-module-systems" class="md-header-anchor"></a><span>Legacy module systems</span></h4><p><code>CommonJS</code><span>, </span><code>AMD</code><span>, </span><code>UMD</code><span>, ...</span></p><h4><a name="legacy-module-loader--bundler" class="md-header-anchor"></a><span>Legacy Module Loader / Bundler</span></h4><p><code>RequireJS</code><span>, </span><code>SystemJS</code><span>, </span><code>browserify</code><span>, ...</span></p><h3><a name="modules-are-async" class="md-header-anchor"></a><span>Modules are async</span></h3><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-comment">// Use URI format as follows: "./myFile.js"</span></span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-operator">&lt;</span><span class="cm-variable">script</span> <span class="cm-variable">src</span><span class="cm-operator">=</span><span class="cm-string">"./myFile.js"</span> <span class="cm-variable">type</span><span class="cm-operator">=</span><span class="cm-string">"module"</span><span class="cm-operator">&gt;</span> <span class="cm-comment">// type implies "defer"</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">import</span> (<span class="cm-string">"./myFile.js"</span>).<span class="cm-property">then</span>( <span class="cm-def">modules</span> <span class="cm-operator">=&gt;</span> <span class="cm-meta">...</span> )</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-comment">// invasive, transitive impact</span></span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 70px;"></div><div class="CodeMirror-gutters" style="display: none; height: 70px;"></div></div></div></pre><h3><a name="import-variants" class="md-header-anchor"></a><span>Import Variants</span></h3><p><span>Always explicit!</span></p><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation" style=""><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-comment">// most used</span></span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">import</span> <span class="cm-string">"module-name"</span>;</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">import</span> { <span class="cm-def">export1</span>, <span class="cm-def">export2</span> } <span class="cm-keyword">from</span> <span class="cm-string">"module-name"</span>;</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span cm-text="">​</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-comment">// other variants</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">import</span> <span class="cm-def">defaultExport</span> <span class="cm-keyword">from</span> <span class="cm-string">"module-name"</span>;</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">import</span> <span class="cm-keyword">*</span> <span class="cm-keyword">as</span> <span class="cm-def">name</span> <span class="cm-keyword">from</span> <span class="cm-string">"module-name"</span>;</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">import</span> { <span class="cm-keyword">export</span> } <span class="cm-keyword">from</span> <span class="cm-string">"module-name"</span>;</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">import</span> { <span class="cm-keyword">export</span> <span class="cm-keyword">as</span> <span class="cm-def">alias</span> } <span class="cm-keyword">from</span> <span class="cm-string">"module-name"</span>;</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">var</span> <span class="cm-def">promise</span> <span class="cm-operator">=</span> <span class="cm-keyword">import</span>(<span class="cm-string">"module-name"</span>);</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 176px;"></div><div class="CodeMirror-gutters" style="display: none; height: 176px;"></div></div></div></pre><h3><a name="export-variants" class="md-header-anchor"></a><span>Export Variants</span></h3><p><span>Always explicit!</span></p><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation" style=""><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-comment">// most used</span></span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">export</span> { <span class="cm-variable">name1</span>, <span class="cm-variable">name2</span>, <span class="cm-meta">...</span> , <span class="cm-variable">nameN</span> };</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span cm-text="">​</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-comment">// other variants</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">export</span> <span class="cm-keyword">function</span> <span class="cm-def">FunctionName</span>() { .. }</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">export</span> <span class="cm-keyword">const</span> <span class="cm-def">name1</span>, <span class="cm-def">name2</span>, <span class="cm-meta">...</span> , <span class="cm-def">nameN</span>; <span class="cm-comment">// or let</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">export</span> <span class="cm-keyword">class</span> <span class="cm-def">ClassName</span> { .. }</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">export</span> <span class="cm-keyword">default</span> <span class="cm-variable">expression</span>;</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">export</span> { <span class="cm-variable">name1</span> <span class="cm-keyword">as</span> <span class="cm-keyword">default</span>, .. };</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">export</span> <span class="cm-keyword">*</span> <span class="cm-keyword">from</span> .. ;</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">export</span> { <span class="cm-variable">name1</span>, <span class="cm-variable">name2</span>, <span class="cm-meta">...</span> , <span class="cm-variable">nameN</span> } <span class="cm-keyword">from</span> .. ;</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 194px;"></div><div class="CodeMirror-gutters" style="display: none; height: 194px;"></div></div></div></pre><h3><a name="impacts" class="md-header-anchor"></a><span>Impacts</span></h3><ul><li><span>implicit &quot;use-strict&quot; exports are read-only !</span></li><li><span>no Global object, no Global &quot;this&quot;, no Global hoisting</span></li><li><span>implicit &quot;defer&quot; mode =&gt; </span><code>document.writeln</code><span> is no longer useful</span></li><li><span>Modules are Namespaces</span></li><li><span>Modules are Singletons</span></li></ul><h3><a name="sop---single-origin-policy" class="md-header-anchor"></a><span>SOP - Single Origin Policy</span></h3><ul><li><span>Modules are subject to the SOP</span></li><li><span>Problem at construction time: the File System is a </span><strong><span>null origin</span></strong></li></ul><h3><a name="useful-tools" class="md-header-anchor"></a><span>Useful Tools</span></h3><ul><li><span>Developer Mode (suppress SOP) -&gt; don&#39;t forget to set back!</span></li><li><span>Local Webserver</span></li><li><span>Disable cache!</span></li><li><span>Bundler (Rollup, Parcel, Webpack, ...)</span></li><li><span>Start Browser in Debug mode</span></li></ul><h3><a name="resources" class="md-header-anchor"></a><span>Resources</span></h3><ul><li><a href='https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/import' target='_blank' class='url'>https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/import</a></li><li><a href='http://exploringjs.com/es6/ch_modules.html' target='_blank' class='url'>http://exploringjs.com/es6/ch_modules.html</a></li></ul><p>&nbsp;</p><h2><a name="13-transpilers-typescript-purescript-elm" class="md-header-anchor"></a><span>13. Transpilers: TypeScript, PureScript, Elm</span></h2><blockquote><p><span>&quot;The limits of my language are the limits of my world.&quot;</span></p><ul><li><span>Ludwig Wittgenstein, Tractatus Logico-Philosophicus</span></li></ul></blockquote><h3><a name="what-they-have-in-common" class="md-header-anchor"></a><span>What they have in common</span></h3><ul><li><p><span>All are transpiling to JavaScript !</span></p></li><li><p><span>Allow React / Elm Architecture for functional JavaScript / SPA</span></p><ul><li><span>TypeScript + React</span></li><li><span>PureScript + Pux / Halogen</span></li><li><span>Elm</span></li></ul></li></ul><h3><a name="the-cycle" class="md-header-anchor"></a><span>The Cycle</span></h3><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-variable">View</span> <span class="cm-operator">-&gt;</span> <span class="cm-variable">Action</span> <span class="cm-operator">-&gt;</span> <span class="cm-variable">State</span> <span class="cm-operator">-&gt;</span> <span class="cm-variable">State</span> <span class="cm-variable">___________</span><span class="cm-operator">|</span></span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-operator">^</span><span class="cm-tab" role="presentation" cm-text="	">  </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-tab" role="presentation" cm-text="	">    </span><span class="cm-operator">|</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-operator">|</span><span class="cm-variable">__________________________________________</span><span class="cm-operator">|</span></span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 53px;"></div><div class="CodeMirror-gutters" style="display: none; height: 53px;"></div></div></div></pre><h3><a name="typescript" class="md-header-anchor"></a><span>TypeScript</span></h3><ul><li><span>Typed state</span></li><li><span>Actions as functions / lamdas</span></li><li><span>State immutability with discipline</span></li><li><span>Object / component abstraction</span></li></ul><h3><a name="elm" class="md-header-anchor"></a><span>Elm</span></h3><ul><li><span>Typed state</span></li><li><span>Action type with values</span></li><li><span>State is immutable</span></li><li><span>Update function is a fold</span></li><li><span>Function composition</span></li></ul><h3><a name="purescript--pux" class="md-header-anchor"></a><span>PureScript / Pux</span></h3><ul><li><span>Like Elm</span></li><li><span>But even more Haskell-ish</span></li><li><a href='https://try.purescript.org/' target='_blank' class='url'>https://try.purescript.org/</a></li></ul><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="javascript"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="javascript"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 4px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation" style=""><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-comment">// signature</span></span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-comment">// name  quantifier  type variables</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-variable">konst</span> :: <span class="cm-variable">forall</span> <span class="cm-variable">a</span> <span class="cm-variable">b</span> . <span class="cm-property">a</span> <span class="cm-operator">-&gt;</span> <span class="cm-variable">b</span> <span class="cm-operator">-&gt;</span> <span class="cm-variable">a</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-comment">// definition</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-variable">konst</span> <span class="cm-variable">x</span> <span class="cm-variable">y</span> <span class="cm-operator">=</span> <span class="cm-variable">x</span></span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 88px;"></div><div class="CodeMirror-gutters" style="display: none; height: 88px;"></div></div></div></pre><p>&nbsp;</p><h3><a name="calling-javascript-ffi" class="md-header-anchor"></a><span>Calling JavaScript (FFI)</span></h3><figure><table><thead><tr><th><span>TypeScript</span></th><th><span>Type declaration</span></th></tr></thead><tbody><tr><td><strong><span>PureScript</span></strong></td><td><strong><span>Type declaration</span></strong></td></tr><tr><td><strong><span>Elm</span></strong></td><td><strong><span>Port / Flag</span></strong></td></tr></tbody></table></figure><h3><a name="applicability" class="md-header-anchor"></a><span>Applicability</span></h3><figure><table><thead><tr><th><span>TypeScript</span></th><th><span>JS Environment</span></th></tr></thead><tbody><tr><td><strong><span>PureScript</span></strong></td><td><strong><span>JS Environment</span></strong></td></tr><tr><td><strong><span>Elm</span></strong></td><td><strong><span>Browser</span></strong></td></tr></tbody></table></figure><h3><a name="paradigm" class="md-header-anchor"></a><span>Paradigm</span></h3><figure><table><thead><tr><th><span>TypeScript</span></th><th><span>OO with Generics</span></th></tr></thead><tbody><tr><td><strong><span>PureScript</span></strong></td><td><strong><span>Functional</span></strong></td></tr><tr><td><strong><span>Elm</span></strong></td><td><strong><span>Functional</span></strong></td></tr></tbody></table></figure><h3><a name="approach" class="md-header-anchor"></a><span>Approach</span></h3><figure><table><thead><tr><th><span>TypeScript</span></th><th><span>Language</span></th></tr></thead><tbody><tr><td><strong><span>PureScript</span></strong></td><td><strong><span>Language &amp; Tools</span></strong></td></tr><tr><td><strong><span>Elm</span></strong></td><td><strong><span>Programming System</span></strong></td></tr></tbody></table></figure><h3><a name="cool" class="md-header-anchor"></a><span>Cool</span></h3><figure><table><thead><tr><th><span>TypeScript</span></th><th><span>Sum (union) type , String Literal type</span></th></tr></thead><tbody><tr><td><strong><span>PureScript</span></strong></td><td><strong><span>Eff Monad, [GADT]</span></strong></td></tr><tr><td><strong><span>Elm</span></strong></td><td><strong><span>Time travel debug , SemVer guarantee</span></strong></td></tr></tbody></table></figure><h3><a name="more-transpilers" class="md-header-anchor"></a><span>More Transpilers</span></h3><figure><table><thead><tr><th><span>ClojureScript</span></th><th><span>Clojure (Lisp)</span></th></tr></thead><tbody><tr><td><strong><span>GHCJS</span></strong></td><td><strong><span>Haskell</span></strong></td></tr><tr><td><strong><span>Babel</span></strong></td><td><strong><span>JS</span></strong></td></tr><tr><td><strong><span>CoffeeScript</span></strong></td><td><strong><span>JS++</span></strong></td></tr><tr><td><strong><span>GrooScript</span></strong></td><td><strong><span>Groovy</span></strong></td></tr></tbody></table></figure><p>&nbsp;</p><h2><a name="14-crazy-javascript" class="md-header-anchor"></a><span>14. Crazy JavaScript</span></h2></div>
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