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<!DOCTYPE HTML>
<html lang="ru">
<head>
<title>Three Men in a Boat (To Say Nothing of the Callback)</title>
<meta charset="UTF-8">
<meta name="viewport" content="width=792, user-scalable=no">
<link rel="stylesheet" href="themes/yandex/styles/screen.css">
<link rel="stylesheet" href="styles/print.css" media="print">
<link rel="stylesheet" href="styles/idea.min.css">
<link rel="shortcut icon" href="favicon.ico">
</head>
<body class="list">
<header class="caption">
<h1>Three Men in a Boat <br/>(To Say Nothing of the Callback)</h1>
<p>Zhigalov Sergey, <a href="http://yandex.ru/">Yandex</a></p>
</header>
<section class="slide shout" id="cover">
<div>
<h2>Three Men in a Boat <br/>(To Say Nothing of the Callback)</h2>
<div class="info">
<p class="author">Zhigalov Sergey</p>
<p class="location">Frontend Union Conf, 2015</p>
</div>
</div>
</section>
<section class="slide">
<h2>Flights to St. Petersburg</h2>
<ol>
<li>Get list of airlines</li>
<li>Get flight cost</li>
<li>Sort airlines by cost in ascending order</li>
</ol>
</section>
<section class="slide section cover">
<h3>Callback</h3>
<div style="background-image: url('images/000.png');" class="cover-image"></div>
</section>
<section class="slide">
<pre class="javascript">
<code>function getFlights(cb) {</code>
<code> getAirlines(function (err, airlines) {</code>
<code> if (err) { return cb(err); }</code>
<code> var flightsCost = [];</code>
<code> var airlinesCounter = airlines.length;</code>
<code> airlines.forEach(function (airline, index) {</code>
<code> getCost(airline, function (err, cost) {</code>
<code> if (err) { return cb(err); }</code>
<code> flightsCost[index] = cost;</code>
<code> if (--airlinesCounter === 0) {</code>
<code> var sortedAirlines = sortAirlines(airlines, flightsCost);</code>
<code> cb(null, sortedAirlines);</code>
<code> }</code>
<code> })</code>
<code> });</code>
<code> });</code>
<code>}</code>
</pre>
</section>
<section class="slide cover w copyright" style="text-align: center;">
<img class="myGif" src="images/catIsSad.gif" alt="catIsSad" />
</section>
<section class="slide">
<pre class="transparent-code javascript" style="margin-top: 10px">
<code>function getFlights(cb) {</code>
<code> <mark>Get list of airlines</mark>(function (err, airlines) {</code>
<code> if (err) { return cb(err); }</code>
<code> var flightsCost = [];</code>
<code> var airlinesCounter = airlines.length;</code>
<code> airlines.forEach(function (airline, index) {</code>
<code> <mark>Get flight cost</mark>(airline, function (err, cost) {</code>
<code> if (err) { return cb(err); }</code>
<code> flightsCost[index] = cost;</code>
<code> if (--airlinesCounter === 0) {</code>
<code> var sortedAirlines = <mark>Sort airlines</mark>(airlines, flightsCost);</code>
<code> cb(null, sortedAirlines);</code>
<code> }</code>
<code> })</code>
<code> });</code>
<code> });</code>
<code>}</code>
</pre>
<pre class="translucent-code javascript">
<code>function getFlights(cb) {</code>
<code> <mark>Get list of airlines</mark>(function (err, airlines) {</code>
<code> if (err) { return cb(err); }</code>
<code> var flightsCost = [];</code>
<code> var airlinesCounter = airlines.length;</code>
<code> airlines.forEach(function (airline, index) {</code>
<code> <mark>Get flight cost</mark>(airline, function (err, cost) {</code>
<code> if (err) { return cb(err); }</code>
<code> flightsCost[index] = cost;</code>
<code> if (--airlinesCounter === 0) {</code>
<code> var sortedAirlines = <mark>Sort airlines</mark>(airlines, flightsCost);</code>
<code> cb(null, sortedAirlines);</code>
<code> }</code>
<code> })</code>
<code> });</code>
<code> });</code>
<code>}</code>
</pre>
</section>
<section class="slide">
<pre class="transparent-code javascript">
<code>function getFlights(cb) {</code>
<code> getAirlines(function (err, airlines) {</code>
<code> if (err) { return cb(err); }</code>
<code> var flightsCost = [];</code>
<code> var airlinesCounter = airlines.length;</code>
<code> airlines.forEach(function (airline, index) {</code>
<code> getCost(airline, function (err, cost) {</code>
<code> if (err) { return cb(err); }</code>
<code> flightsCost[index] = cost;</code>
<code> if (--airlinesCounter === 0) {</code>
<code> var sortedAirlines = sortAirlines(airlines, flightsCost);</code>
<code> cb(null, sortedAirlines);</code>
<code> <mark>}</mark></code>
<code> <mark>})</mark></code>
<code> <mark>});</mark></code>
<code> <mark>});</mark></code>
<code><mark>}</mark></code>
</pre>
<pre class="translucent-code javascript">
<code>function getFlights(cb) {</code>
<code> getAirlines(function (err, airlines) {</code>
<code> if (err) { return cb(err); }</code>
<code> var flightsCost = [];</code>
<code> var airlinesCounter = airlines.length;</code>
<code> airlines.forEach(function (airline, index) {</code>
<code> getCost(airline, function (err, cost) {</code>
<code> if (err) { return cb(err); }</code>
<code> flightsCost[index] = cost;</code>
<code> if (--airlinesCounter === 0) {</code>
<code> var sortedAirlines = sortAirlines(airlines, flightsCost);</code>
<code> cb(null, sortedAirlines);</code>
<code> <mark>}</mark></code>
<code> <mark>})</mark></code>
<code> <mark>});</mark></code>
<code> <mark>});</mark></code>
<code><mark>}</mark></code>
</pre>
</section>
<section class="slide">
<pre class="transparent-code javascript">
<code>function getFlights(cb) {</code>
<code> getAirlines(function (err, airlines) {</code>
<code> if (err) { return <mark>cb(err);</mark> }</code>
<code> var flightsCost = [];</code>
<code> var airlinesCounter = airlines.length;</code>
<code> airlines.forEach(function (airline, index) {</code>
<code> getCost(airline, function (err, cost) {</code>
<code> if (err) { return <mark>cb(err);</mark> }</code>
<code> flightsCost[index] = cost;</code>
<code> if (--airlinesCounter === 0) {</code>
<code> var sortedAirlines = sortAirlines(airlines, flightsCost);</code>
<code> <mark>cb(null, sortedAirlines);</mark></code>
<code> }</code>
<code> })</code>
<code> });</code>
<code> });</code>
<code>}</code>
</pre>
<pre class="translucent-code javascript">
<code>function getFlights(cb) {</code>
<code> getAirlines(function (err, airlines) {</code>
<code> if (err) { return <mark>cb(err);</mark> }</code>
<code> var flightsCost = [];</code>
<code> var airlinesCounter = airlines.length;</code>
<code> airlines.forEach(function (airline, index) {</code>
<code> getCost(airline, function (err, cost) {</code>
<code> if (err) { return <mark>cb(err);</mark> }</code>
<code> flightsCost[index] = cost;</code>
<code> if (--airlinesCounter === 0) {</code>
<code> var sortedAirlines = sortAirlines(airlines, flightsCost);</code>
<code> <mark>cb(null, sortedAirlines);</mark></code>
<code> }</code>
<code> })</code>
<code> });</code>
<code> });</code>
<code>}</code>
</pre>
</section>
<section class="slide">
<pre class="transparent-code javascript">
<code>function getFlights(cb) {</code>
<code> getAirlines(function (err, airlines) {</code>
<code> <mark>if (err) { return cb(err); }</mark></code>
<code> var flightsCost = [];</code>
<code> var airlinesCounter = airlines.length;</code>
<code> airlines.forEach(function (airline, index) {</code>
<code> getCost(airline, function (err, cost) {</code>
<code> <mark>if (err) { return cb(err); }</mark></code>
<code> flightsCost[index] = cost;</code>
<code> if (--airlinesCounter === 0) {</code>
<code> var sortedAirlines = sortAirlines(airlines, flightsCost);</code>
<code> cb(null, sortedAirlines);</code>
<code> }</code>
<code> })</code>
<code> });</code>
<code> });</code>
<code>}</code>
</pre>
<pre class="translucent-code javascript">
<code>function getFlights(cb) {</code>
<code> getAirlines(function (err, airlines) {</code>
<code> <mark>if (err) { return cb(err); }</mark></code>
<code> var flightsCost = [];</code>
<code> var airlinesCounter = airlines.length;</code>
<code> airlines.forEach(function (airline, index) {</code>
<code> getCost(airline, function (err, cost) {</code>
<code> <mark>if (err) { return cb(err); }</mark></code>
<code> flightsCost[index] = cost;</code>
<code> if (--airlinesCounter === 0) {</code>
<code> var sortedAirlines = sortAirlines(airlines, flightsCost);</code>
<code> cb(null, sortedAirlines);</code>
<code> }</code>
<code> })</code>
<code> });</code>
<code> });</code>
<code>}</code>
</pre>
</section>
<section class="slide">
<pre class="transparent-code javascript">
<code>function getFlights(cb) {</code>
<code> getAirlines(function (err, airlines) {</code>
<code> if (err) { return cb(err); }</code>
<code> var flightsCost = [];</code>
<code> var airlinesCounter = <mark>airlines.length;</mark></code>
<code> airlines.forEach(function (airline, index) {</code>
<code> getCost(airline, function (err, cost) {</code>
<code> if (err) { return cb(err); }</code>
<code> flightsCost[index] = cost;</code>
<code> if (--airlinesCounter === 0) {</code>
<code> var sortedAirlines = sortAirlines(airlines, flightsCost);</code>
<code> cb(null, unpaidairlines);</code>
<code> }</code>
<code> })</code>
<code> });</code>
<code> });</code>
<code>}</code>
</pre>
<pre class="translucent-code javascript">
<code>function getFlights(cb) {</code>
<code> getAirlines(function (err, airlines) {</code>
<code> if (err) { return cb(err); }</code>
<code> var flightsCost = [];</code>
<code> var airlinesCounter = <mark>airlines.length;</mark></code>
<code> airlines.forEach(function (airline, index) {</code>
<code> getCost(airline, function (err, cost) {</code>
<code> if (err) { return cb(err); }</code>
<code> flightsCost[index] = cost;</code>
<code> if (--airlinesCounter === 0) {</code>
<code> var sortedAirlines = sortAirlines(airlines, flightsCost);</code>
<code> cb(null, sortedAirlines);</code>
<code> }</code>
<code> })</code>
<code> });</code>
<code> });</code>
<code>}</code>
</pre>
</section>
<section class="slide">
<pre class="transparent-code javascript">
<code>function getFlights(cb) {</code>
<code> getAirlines(function (err, airlines) {</code>
<code> if (err) { return cb(err); }</code>
<code> <mark>var flightsCost = [];</mark></code>
<code> <mark>var airlinesCounter = airlines.length;</mark></code>
<code> airlines.forEach(function (airline, index) {</code>
<code> getCost(airline, function (err, cost) {</code>
<code> if (err) { return cb(err); }</code>
<code> <mark>flightsCost[index]</mark> = cost;</code>
<code> if (<mark>--airlinesCounter</mark> === 0) {</code>
<code> var sortedAirlines = sortAirlines(airlines, flightsCost);</code>
<code> cb(null, sortedAirlines);</code>
<code> }</code>
<code> })</code>
<code> });</code>
<code> });</code>
<code>}</code>
</pre>
<pre class="translucent-code javascript">
<code>function getFlights(cb) {</code>
<code> getAirlines(function (err, airlines) {</code>
<code> if (err) { return cb(err); }</code>
<code> <mark>var flightsCost = [];</mark></code>
<code> <mark>var airlinesCounter = airlines.length;</mark></code>
<code> airlines.forEach(function (airline, index) {</code>
<code> getCost(airline, function (err, cost) {</code>
<code> if (err) { return cb(err); }</code>
<code> <mark>flightsCost[index]</mark> = cost;</code>
<code> if (<mark>--airlinesCounter</mark> === 0) {</code>
<code> var sortedAirlines = sortAirlines(airlines, flightsCost);</code>
<code> cb(null, sortedAirlines);</code>
<code> }</code>
<code> })</code>
<code> });</code>
<code> });</code>
<code>}</code>
</pre>
</section>
<section class="slide">
<table>
<thead>
<tr>
<th scope="col">Criteria</th>
<th scope="col">Callback</th>
</tr>
</thead>
<tbody>
<tr>
<td>overheads</td>
<td class="good">no</td>
</tr>
<tr>
<td>level of nesting</td>
<td class="bad">5</td>
</tr>
<tr>
<td>visual noise</td>
<td class="bad">yes</td>
</tr>
<tr>
<td>separation of data and error</td>
<td class="bad">no</td>
</tr>
<tr>
<td>code duplication</td>
<td class="bad">yes</td>
</tr>
<tr>
<td>missed error</td>
<td class="bad">yes</td>
</tr>
<tr>
<td>linear code</td>
<td class="bad">no</td>
</tr>
</tbody>
</table>
</section>
<section class="slide section cover">
<h3>Promises</h3>
<div style="background-image: url('images/001.png');" class="cover-image"></div>
</section>
<section class="slide">
<h2>Promises</h2>
<pre class="javascript">
<code><mark>myPromise()</mark></code>
<code> .then(function onSuccess() { return data; },</code>
<code> function onRejected() { ... })</code>
<code> .then(function(data) { ... })</code>
<code> </code>
</pre>
</section>
<section class="slide">
<h2>Promises</h2>
<pre class="javascript">
<code>myPromise()</code>
<code> .then(function <mark>onSuccess</mark>() { return data; },</code>
<code> function <mark>onRejected</mark>() { ... })</code>
<code> .then(function(data) { ... })</code>
<code> </code>
</pre>
<div style="text-align: center"><img src="images/promiseInit.png" alt="promise" height="180"/></div>
</section>
<section class="slide">
<h2>Promises</h2>
<pre class="javascript">
<code>myPromise()</code>
<code> .then(function onSuccess() { <mark>return data;</mark> },</code>
<code> function onRejected() { ... })</code>
<code> .then(function(<mark>data</mark>) { ... })</code>
<code> </code>
</pre>
<div style="text-align: center"><img src="images/promiseInit.png" alt="promise" height="180"/></div>
</section>
<section class="slide">
<h2>Promises</h2>
<pre class="javascript">
<code>myPromise()</code>
<code> .then(function onSuccess() { return data; },</code>
<code> function onRejected() { ... })</code>
<code> .then(function(data) { ... })</code>
<code> </code>
</pre>
<div style="text-align: center"><img src="images/promiseInit.png" alt="promise" height="180"/></div>
<p><a href="https://promisesaplus.com/">Promises/A+</a></p>
<p><a href="https://vimeo.com/74925301">Михаил Давыдов "Promise – это не больно"</a></p>
</section>
<section class="slide">
<table style="width: 100%; margin-top: -35px;">
<thead>
<tr>
<th scope="col">library</th>
<th scope="col">time(ms)</th>
<th scope="col">memory(MB)</th>
</tr>
</thead>
<tbody>
<tr>
<td>callbacks</td>
<td>211</td>
<td>25.57</td>
</tr>
<tr>
<td><p class="github"><a href="https://github.com/petkaantonov/bluebird">bluebird</a></p></td>
<td>389</td>
<td>53.49</td>
</tr>
<tr>
<td><p class="github"><a href="https://github.com/tildeio/rsvp.js/">RSVP.js</a></p></td>
<td>785</td>
<td>108.14</td>
</tr>
<tr>
<td><p class="github"><a href="https://github.com/dfilatov/vow">Vow</a></p></td>
<td>798</td>
<td>102.08</td>
</tr>
<tr>
<td><p class="github"><a href="https://github.com/cujojs/when">when.js</a></p></td>
<td>851</td>
<td>60.46</td>
</tr>
<tr>
<td><p class="github"><a href="https://github.com/calvinmetcalf/lie">lie</a></p></td>
<td>1065</td>
<td>187.69</td>
</tr>
<tr>
<td><p class="github"><a href="https://github.com/lvivski/davy">Davy Jones</a></p></td>
<td>1298</td>
<td>135.43</td>
</tr>
<!--<tr>-->
<!--<td>callbacks-caolan-async-parallel.js</td>-->
<!--<td>1780</td>-->
<!--<td>101.11</td>-->
<!--</tr>-->
<tr>
<td><p class="github"><a href="https://github.com/then/promise">then promise</a></p></td>
<td>2438</td>
<td>338.91</td>
</tr>
<!--<tr>-->
<!--<td>promises-ecmascript6-native.js</td>-->
<!--<td>3532</td>-->
<!--<td>301.96</td>-->
<!--</tr>-->
<!--<tr>-->
<!--<td>promises-medikoo-deferred.js</td>-->
<!--<td>4207</td>-->
<!--<td>357.60</td>-->
<!--</tr>-->
<!--<tr>-->
<!--<td>promises-obvious-kew.js</td>-->
<!--<td>8311</td>-->
<!--<td>559.24</td>-->
<!--</tr>-->
</tbody>
</table>
<p style="font-size: small; color: darkgrey;">* results for 10000 parallel executions, 1 ms per I/O op (<a
href="https://github.com/petkaantonov/bluebird/tree/master/benchmark">Original</a>)</p>
</section>
<section class="slide">
<h2><small>Promises.</small> Bluebird</h2>
<pre class="javascript">
<code>function myFunction(arg1, arg2, cb) {</code>
<code> cb(err, result);</code>
<code>}</code>
<code>var myPromisifyFunction = Promise.promisify(myFunction);</code>
<code> </code>
<code>myPromisifyFunction()</code>
<code> .then(function() { ... })</code>
</pre>
<img src="images/bluebird.png" alt="bluebird" style="position: absolute; right: 40px; top: 26px;"/>
<div style="margin-top: 35px;">
<p class="github"><a href="https://github.com/petkaantonov/bluebird">petkaantonov/bluebird</a></p>
</div>
</section>
<section class="slide">
<h2>Promises</h2>
<pre class="javascript">
<code>function getAirlinesCb(cb) {</code>
<code> setTimeout(function () {</code>
<code> cb(null, 'Airline #123');</code>
<code> }, 0);</code>
<code>}</code>
</pre>
<br/>
<pre class="javascript">
<code>var getAirlines = Promise.promisify(getAirlinesCb);</code>
</pre>
</section>
<section class="slide">
<h2>Promises</h2>
<pre class="javascript">
<code>function getFlights() {</code>
<code> return getAirlines()</code>
<code> .then(getCosts)</code>
<code> .then(sortAirlines)</code>
<code> .catch(onReject);</code>
<code>}</code>
</pre>
</section>
<section class="slide">
<h2>Promises</h2>
<pre class="javascript">
<code>function getFlights() {</code>
<code> return getAirlines()</code>
<code> .then(<mark>getCosts</mark>)</code>
<code> .then(sortAirlines)</code>
<code> .catch(onReject);</code>
<code>}</code>
</pre>
</section>
<section class="slide">
<h2><small>Promises.</small> getCosts</h2>
<pre class="javascript">
<code>function getCosts(airlines) {</code>
<code> return Promise.props({</code>
<code> airlines: airlines,</code>
<code> flightsCost: Promise.all(airlines.map(getCost))</code>
<code> });</code>
<code>}</code>
</pre>
</section>
<section class="slide">
<h2>Promise</h2>
<pre class="javascript">
<code>function getFlights() {</code>
<code> return getAirlines()</code>
<code> .then(function (airlines) {</code>
<code> return Promise.props({</code>
<code> airlines: airlines,</code>
<code> flightsCost: Promise.all(airlines.map(getCost))</code>
<code> });</code>
<code> })</code>
<code> .then(sortAirlines);</code>
<code>}</code>
<code> </code>
<code>getFlights</code>
<code> .then(function (data) { console.log(data); })</code>
<code> .catch(function (err) { console.error(err); });</code>
</pre>
</section>
<section class="slide">
<table style="width: 100%;">
<thead>
<tr>
<th scope="col">Criteria</th>
<th scope="col">Callback</th>
<th scope="col">Promises</th>
</tr>
</thead>
<tbody>
<tr>
<td>overheads</td>
<td class="good">no</td>
<td class="bad">yes</td>
</tr>
<tr>
<td>level of nesting</td>
<td class="bad">5</td>
<td class="neutral">2</td>
</tr>
<tr>
<td>visual noise</td>
<td class="bad">yes</td>
<td class="neutral">no</td>
</tr>
<tr>
<td>separation of data and error</td>
<td class="bad">no</td>
<td class="neutral">yes</td>
</tr>
<tr>
<td>code duplication</td>
<td class="bad">yes</td>
<td class="good">no</td>
</tr>
<tr>
<td>missed error</td>
<td class="bad">yes</td>
<td class="good">no</td>
</tr>
<tr>
<td>linear code</td>
<td class="bad">no</td>
<td class="neutral">yes</td>
</tr>
</tbody>
</table>
</section>
<section class="slide">
<h2>Perfect code</h2>
<pre class="javascript">
<code>function getFlights() {</code>
<code> var airlines = <mark>Get list of airlines</mark>()</code>
<code> var flightsCost = airlines.map(<mark>Get flight cost</mark>);</code>
<code> return <mark>Sort airlines</mark>(airlines, flightsCost);</code>
<code>};</code>
</pre>
</section>
<section class="slide">
<h2>Perfect code</h2>
<pre class="javascript">
<code>function getFlights() {</code>
<code> var airlines = getAirlines();</code>
<code> var flightsCost = airlines.map(getCost);</code>
<code> return sortAirlines(airlines, flightsCost);</code>
<code>}</code>
</pre>
</section>
<section class="slide">
<h2><small>Perfect code.</small> Sync</h2>
<pre class="javascript">
<code>function getFlights() {</code>
<code> var airlines = getAirlines<mark>Sync</mark>();</code>
<code> var flightsCost = airlines.map(getCost<mark>Sync</mark>);</code>
<code> return sortAirlines(airlines, flightsCost);</code>
<code>}</code>
</pre>
</section>
<section class="slide">
<h2><small>Perfect code.</small> Generator</h2>
<pre class="javascript">
<code>function <mark>*</mark>getFlights() {</code>
<code> var airlines = <mark>yield</mark> getAirlines();</code>
<code> var flightsCost = <mark>yield</mark> airlines.map(getCost);</code>
<code> return sortAirlines(airlines, flightsCost);</code>
<code>}</code>
</pre>
</section>
<section class="slide cover w copyright" style="text-align: center; ">
<img class="myGif" src="images/catsShock.gif" alt="catsShock" />
</section>
<section class="slide">
<h2><small>Perfect code.</small> Generator</h2>
<pre class="javascript">
<code>co(function *getFlights() {</code>
<code> var airlines = yield getAirlines();</code>
<code> var flightsCost = yield airlines.map(getCost);</code>
<code> return sortAirlines(airlines, flightsCost);</code>
<code>}).then(function (data) { console.log(data); });</code>
</pre>
</section>
<section class="slide section cover">
<h3>Generators</h3>
<div style="background-image: url('images/002.png');" class="cover-image"></div>
</section>
<section class="slide">
<h2>Generator</h2>
<blockquote>A generator can pause itself in mid-execution, and can be resumed either right away or at a later
time.
</blockquote>
<p>ES6</p>
</section>
<section class="slide">
<h2>Generator</h2>
<blockquote>A generator can pause itself in mid-execution, and can be resumed either right away or at a later
time.
</blockquote>
<p><strike>ES6</strike> ES2015</p>
</section>
<section class="slide">
<h2><small>Generator.</small> Declaration</h2>
<pre class="javascript">
<code>function <mark>*</mark>myGenerator(name) {</code>
<code> console.log('Hello, ' + name);</code>
<code>}</code>
</pre>
</section>
<section class="slide">
<h2><small>Generator.</small> Run</h2>
<pre class="javascript">
<code>function *myGenerator(name) {</code>
<code> console.log('Hello, ' + name);</code>
<code>}</code>
<code> </code>
<code>myGenerator('Frontend Union Conf');</code>
</pre>
<div class="console_port">
<h3>Console:</h3>
<pre class="console">
<code>></code>
</pre>
</div>
</section>
<section class="slide">
<h2><small>Generator.</small> Iterator</h2>
<blockquote>An iterator is a structured pattern for pulling information from a source in one-at-a-time fashion.</blockquote>
<pre class="javascript">
<code>it.next()</code>
</pre>
<div class="console_port">
<h3>Console:</h3>
<pre class="console">
<code>{ value: {...}, done: false}</code>
<code>></code>
</pre>
</div>
</section>
<section class="slide">
<h2><small>Generator.</small> Run</h2>
<pre class="javascript">
<code>function *myGenerator(name) {</code>
<code> console.log('Hello, ' + name);</code>
<code>}</code>
<code> </code>
<code>var it = myGenerator('Frontend Union Conf');</code>
<code>it.next();</code>
</pre>
<div class="console_port">
<h3>Console:</h3>
<pre class="console">
<code>Hello, Frontend Union Conf</code>
<code>></code>
</pre>
</div>
</section>
<section class="slide">
<h2><small>Generator.</small> Fibonacci</h2>
<pre class="javascript">
<code>var it = fibonacci();</code>
<code> </code>
</pre>
</section>
<section class="slide">
<h2><small>Generator.</small> Fibonacci</h2>
<pre class="javascript">
<code>var it = fibonacci();</code>
<code> </code>
<code>console.log(it.next().value);</code>
</pre>
<div class="console_position console_port" style="top: 143px">
<h3>Console:</h3>
<pre class="console">
<code>1</code>
<code>></code>
</pre>
</div>
</section>
<section class="slide">
<h2><small>Generator.</small> Fibonacci</h2>
<pre class="javascript">
<code>var it = fibonacci();</code>
<code> </code>
<code>console.log(it.next().value);</code>
<code>console.log(it.next().value);</code>
</pre>
<div class="console_position console_port" style="top: 143px">
<h3>Console:</h3>
<pre class="console">
<code>1</code>
<code>1</code>
<code>></code>
</pre>
</div>
</section>
<section class="slide">
<h2><small>Generator.</small> Fibonacci</h2>
<pre class="javascript">
<code>var it = fibonacci();</code>
<code> </code>
<code>console.log(it.next().value);</code>
<code>console.log(it.next().value);</code>
<code>console.log(it.next().value);</code>
</pre>
<div class="console_position console_port" style="top: 143px">
<h3>Console:</h3>
<pre class="console">
<code>1</code>
<code>1</code>
<code>2</code>
<code>></code>
</pre>
</div>
</section>
<section class="slide">
<h2><small>Generator.</small> Fibonacci</h2>
<pre class="javascript">
<code>var it = fibonacci();</code>
<code> </code>
<code>console.log(it.next().value);</code>
<code>console.log(it.next().value);</code>
<code>console.log(it.next().value);</code>
<code>console.log(it.next().value);</code>
</pre>
<div class="console_position console_port" style="top: 143px">
<h3>Console:</h3>
<pre class="console">
<code>1</code>
<code>1</code>
<code>2</code>
<code>3</code>
<code>></code>
</pre>
</div>
</section>
<section class="slide">
<h2><small>Generator.</small> Fibonacci</h2>
<pre class="javascript">
<code>var it = fibonacci();</code>
<code> </code>
<code>console.log(it.next().value);</code>
<code>console.log(it.next().value);</code>
<code>console.log(it.next().value);</code>
<code>console.log(it.next().value);</code>
<code>console.log(it.next().value);</code>
</pre>
<div class="console_position console_port" style="top: 143px">
<h3>Console:</h3>
<pre class="console">
<code>1</code>
<code>1</code>
<code>2</code>
<code>3</code>
<code>5</code>
<code>></code>
</pre>
</div>
</section>
<section class="slide">
<h2><small>Generator.</small> Fibonacci</h2>
<pre class="javascript">
<code>function *fibonacci() {</code>
<code> var fn1 = 1;</code>
<code> var fn2 = 1;</code>
<code> while (true) {</code>
<code> var current = fn2;</code>
<code> fn2 = fn1;</code>
<code> fn1 = fn1 + current;</code>
<code> yield current;</code>
<code> }</code>
<code>}</code>
</pre>
</section>
<section class="slide">
<h2><small>Generator.</small> yield</h2>
<pre class="javascript">
<code>function *fibonacci() {</code>
<code> var fn1 = 1;</code>
<code> var fn2 = 1;</code>
<code> while (true) {</code>
<code> var current = fn2;</code>
<code> fn2 = fn1;</code>
<code> fn1 = fn1 + current;</code>
<code> <mark>yield current;</mark></code>
<code> }</code>
<code>}</code>
</pre>
</section>
<section class="slide">
<h2><small>Generator.</small> yield</h2>
<pre class="javascript">
<code></code>
<code>function *sum() {</code>
<code> var a = yield;</code>
<code> var b = yield;</code>
<code> console.log(a + b);</code>
<code>}</code>
<code> </code>
<code>var it = sum();</code>
</pre>
<div class="console_position console_port" style="top: 143px">
<h3>Console:</h3>
<pre class="console">
<code>> </code>
<code> </code>
</pre>
</div>
</section>
<section class="slide">
<h2><small>Generator.</small> yield</h2>
<pre class="javascript">
<code></code>
<code>function *sum() {</code>
<code> var a = <mark>yield;</mark></code>
<code> var b = yield;</code>
<code> console.log(a + b);</code>
<code>}</code>
<code> </code>
<code>var it = sum();</code>
<code>it.next();</code>
</pre>
<div class="console_position console_port" style="top: 143px">
<h3>Console:</h3>
<pre class="console">
<code>> </code>
<code> </code>
</pre>
</div>
</section>
<section class="slide">
<h2><small>Generator.</small> yield</h2>
<pre class="javascript">
<code></code>
<code>function *sum() {</code>
<code> var a = <mark>3</mark>;</code>
<code> var b = yield;</code>
<code> console.log(a + b);</code>
<code>}</code>
<code> </code>
<code>var it = sum();</code>
<code>it.next();</code>
<code>it.next(3);</code>
</pre>
<div class="console_position console_port" style="top: 143px">
<h3>Console:</h3>
<pre class="console">
<code>> </code>
<code> </code>
</pre>
</div>
</section>
<section class="slide">
<h2><small>Generator.</small> yield</h2>
<pre class="javascript">
<code></code>
<code>function *sum() {</code>
<code> var a = 3;</code>
<code> var b = <mark>7</mark>;</code>
<code> console.log(a + b);</code>
<code>}</code>
<code> </code>
<code>var it = sum();</code>
<code>it.next();</code>