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<!DOCTYPE html>
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8">
<!--
es6-features ~~ ECMAScript 6 Feature Overview & Comparison
Copyright (c) 2015-2016 Ralf S. Engelschall <rse@engelschall.com>
Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:
The above copyright notice and this permission notice shall be included
in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-->
<title>ECMAScript 6: New Features: Overview and Comparison</title>
<script src="lib/jquery/jquery.js" type="text/javascript"></script>
<script src="lib/director/director.js" type="text/javascript"></script>
<script src="lib/mousetrap/mousetrap.js" type="text/javascript"></script>
<script src="index.js" type="text/javascript"></script>
<link href="index.css" rel="stylesheet" type="text/css"/>
</head>
<body>
<script>
!function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0],p=/^http:/.test(d.location)?'http':'https';if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src=p+'://platform.twitter.com/widgets.js';fjs.parentNode.insertBefore(js,fjs);}}(document, 'script', 'twitter-wjs');</script>0
</script>
<div class="bg">ES6</div>
<div class="head">
<span class="bold">ECMAScript 6</span> — New Features: Overview & Comparison
</div>
<div class="slogan">
See how cleaner and more concise<br/>
your JavaScript code can look and<br/>
<a href="https://github.com/rse/es6-support">start coding</a> in <a href="http://www.ecma-international.org/publications/standards/Ecma-262.htm">ES6</a> <a href="https://github.com/rse/es6-support">now</a> !!
</div>
<div class="statement">
"A good programming language is a<br/>
conceptual universe for thinking<br/>
about programming." — Alan J. Perlis
</div>
<div class="nav">
<!-- ATTENTION: BEGIN OF GENERATED CODE. DO NOT EDIT MANUALLY -->
<ul>
<li class="title">Constants
<ul>
<li class="subtitle subtitle_Constants">
<a href="#Constants">Constants (常量)</a> <i class="fa fa-arrow-circle-right"></i></li>
</ul>
</li>
<li class="title">Scoping
<ul>
<li class="subtitle subtitle_BlockScopedVariables">
<a href="#BlockScopedVariables">Block-Scoped Variables (局部变量)</a> <i class="fa fa-arrow-circle-right"></i></li>
<li class="subtitle subtitle_BlockScopedFunctions">
<a href="#BlockScopedFunctions">Block-Scoped Functions (局部作用域)</a> <i class="fa fa-arrow-circle-right"></i></li>
</ul>
</li>
<li class="title">Arrow Functions (箭头函数)
<ul>
<li class="subtitle subtitle_ExpressionBodies">
<a href="#ExpressionBodies">Expression Bodies (表达式)</a> <i class="fa fa-arrow-circle-right"></i></li>
<li class="subtitle subtitle_StatementBodies">
<a href="#StatementBodies">Statement Bodies (声明式)</a> <i class="fa fa-arrow-circle-right"></i></li>
<li class="subtitle subtitle_Lexicalthis">
<a href="#Lexicalthis">Lexical <code>this</code> (绑定作用域)</a> <i class="fa fa-arrow-circle-right"></i></li>
</ul>
</li>
<li class="title">Extended Parameter Handling (扩展函数参数)
<ul>
<li class="subtitle subtitle_DefaultParameterValues">
<a href="#DefaultParameterValues">Default Parameter Values (参数默认值)</a> <i class="fa fa-arrow-circle-right"></i></li>
<li class="subtitle subtitle_RestParameterrest">
<a href="#RestParameterrest">Rest Parameter (rest 参数)</a> <i class="fa fa-arrow-circle-right"></i></li>
<li class="subtitle subtitle_SpreadOperator">
<a href="#SpreadOperator">Spread Operator (扩展参数)</a> <i class="fa fa-arrow-circle-right"></i></li>
</ul>
</li>
<li class="title">Template Literals (模版字面量)
<ul>
<li class="subtitle subtitle_StringInterpolation">
<a href="#StringInterpolation">String Interpolation (字符串变量)</a> <i class="fa fa-arrow-circle-right"></i></li>
</ul>
</li>
<li class="title">Enhanced Object Properties (增强对象属性)
<ul>
<li class="subtitle subtitle_PropertyShorthand">
<a href="#PropertyShorthand">Property Shorthand (属性缩写)</a> <i class="fa fa-arrow-circle-right"></i></li>
<li class="subtitle subtitle_ComputedPropertyNames">
<a href="#ComputedPropertyNames">Computed Property Names (计算属性名)</a> <i class="fa fa-arrow-circle-right"></i></li>
<li class="subtitle subtitle_MethodProperties">
<a href="#MethodProperties">Method Properties (方法)</a> <i class="fa fa-arrow-circle-right"></i></li>
</ul>
</li>
<li class="title">Destructuring Assignment (解构赋值)
<ul>
<li class="subtitle subtitle_ArrayMatching">
<a href="#ArrayMatching">Array Matching (数组)</a> <i class="fa fa-arrow-circle-right"></i></li>
<li class="subtitle subtitle_ObjectMatchingShorthandNotation">
<a href="#ObjectMatchingShorthandNotation">Object Matching, Shorthand Notation (对象，简写)</a> <i class="fa fa-arrow-circle-right"></i></li>
<li class="subtitle subtitle_ObjectMatchingDeepMatching">
<a href="#ObjectMatchingDeepMatching">Object Matching, Deep Matching (嵌套匹配)</a> <i class="fa fa-arrow-circle-right"></i></li>
<li class="subtitle subtitle_ObjectAndArrayMatchingDefaultValues">
<a href="#ObjectAndArrayMatchingDefaultValues">Object And Array Matching, Default Values (默认值)</a> <i class="fa fa-arrow-circle-right"></i></li>
<li class="subtitle subtitle_ParameterContextMatching">
<a href="#ParameterContextMatching">Parameter Context Matching (参数)</a> <i class="fa fa-arrow-circle-right"></i></li>
<li class="subtitle subtitle_FailSoftDestructuring">
<a href="#FailSoftDestructuring">Fail-Soft Destructuring (不会翻译)</a> <i class="fa fa-arrow-circle-right"></i></li>
</ul>
</li>
<li class="title">Modules (模块)
<ul>
<li class="subtitle subtitle_ValueExportImport">
<a href="#ValueExportImport">Value Export/Import (导入/导入)</a> <i class="fa fa-arrow-circle-right"></i></li>
<li class="subtitle subtitle_DefaultWildcard">
<a href="#DefaultWildcard">Default & Wildcard (默认值 & 通配符)</a> <i class="fa fa-arrow-circle-right"></i></li>
</ul>
</li>
<li class="title">Classes (类)
<ul>
<li class="subtitle subtitle_ClassDefinition">
<a href="#ClassDefinition">Class Definition (类定义)</a> <i class="fa fa-arrow-circle-right"></i></li>
<li class="subtitle subtitle_ClassInheritance">
<a href="#ClassInheritance">Class Inheritance (类继承)</a> <i class="fa fa-arrow-circle-right"></i></li>
<li class="subtitle subtitle_ClassInheritanceFromExpressions">
<a href="#ClassInheritanceFromExpressions">Class Inheritance, From Expressions (基类入口)</a> <i class="fa fa-arrow-circle-right"></i></li>
<li class="subtitle subtitle_BaseClassAccess">
<a href="#BaseClassAccess">Base Class Access (基类调用)</a> <i class="fa fa-arrow-circle-right"></i></li>
<li class="subtitle subtitle_StaticMembers">
<a href="#StaticMembers">Static Members (静态方法&属性)</a> <i class="fa fa-arrow-circle-right"></i></li>
<li class="subtitle subtitle_GetterSetter">
<a href="#GetterSetter">Getter/Setter (取值&设值)</a> <i class="fa fa-arrow-circle-right"></i></li>
</ul>
</li>
<li class="title">Symbol Type (原始数据类型)
<ul>
<li class="subtitle subtitle_SymbolType">
<a href="#SymbolType">Symbol Type</a> <i class="fa fa-arrow-circle-right"></i></li>
</ul>
</li>
<li class="title">Map/Set
<ul>
<li class="subtitle subtitle_SetDataStructure">
<a href="#SetDataStructure">Set Data-Structure (集合)</a> <i class="fa fa-arrow-circle-right"></i></li>
<li class="subtitle subtitle_MapDataStructure">
<a href="#MapDataStructure">Map Data-Structure (字典)</a> <i class="fa fa-arrow-circle-right"></i></li>
</ul>
</li>
<li class="title">New Built-In Methods (新增内建方法)
<ul>
<li class="subtitle subtitle_ObjectPropertyAssignment">
<a href="#ObjectPropertyAssignment">Object Property Assignment</a> <i class="fa fa-arrow-circle-right"></i></li>
<li class="subtitle subtitle_ArrayElementFinding">
<a href="#ArrayElementFinding">Array Element Finding</a> <i class="fa fa-arrow-circle-right"></i></li>
<li class="subtitle subtitle_StringRepeating">
<a href="#StringRepeating">String Repeating</a> <i class="fa fa-arrow-circle-right"></i></li>
<li class="subtitle subtitle_StringSearching">
<a href="#StringSearching">String Searching</a> <i class="fa fa-arrow-circle-right"></i></li>
</ul>
</li>
<li class="title">Meta-Programming
<ul>
<li class="subtitle subtitle_Proxying">
<a href="#Proxying">Proxying</a> <i class="fa fa-arrow-circle-right"></i></li>
<li class="subtitle subtitle_Reflection">
<a href="#Reflection">Reflection</a> <i class="fa fa-arrow-circle-right"></i></li>
</ul>
</li>
</ul>
<!-- ATTENTION: END OF GENERATED CODE. DO NOT EDIT MANUALLY -->
</div>
<div class="content">
<!-- ATTENTION: BEGIN OF GENERATED CODE. DO NOT EDIT MANUALLY -->
<div id="Constants" class="showcase showcase_Constants"> <div class="title">Constants</div>
<div class="subtitle">Constants (常量)</div>
<div class="desc">Support for constants (also known as "immutable variables"), i.e.,
variables which cannot be re-assigned new content. Notice: this only
makes the variable itself immutable, not its assigned content (for
instance, in case the content is an object, this means the object itself
can still be altered).</div>
<div class="js es6">
<div class="title"><b>ECMAScript 6</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code"><span class="mark"><span class="keyword">const</span> PI</span><span class="punctuation"> = </span><span class="literal">3</span><span class="punctuation">.</span><span class="literal">141593</span><span class="semi">;</span>
PI <span class="punctuation">></span> <span class="literal">3</span><span class="punctuation">.</span><span class="literal">0</span><span class="semi">;</span>
</div>
<i class="icon fa fa-circle"></i>
<i class="icon fa fa-check-circle"></i>
</div>
<div class="arrow"><i class="fa fa-caret-up"></i><i class="fa fa-caret-down"></i></div><div class="js es5">
<div class="title"><b>ECMAScript 5</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code"><span class="comment">// only <span class="keyword">in</span> ES<span class="literal">5</span> through the help <span class="keyword">of</span> object properties</span><span class="comment">
// and only <span class="keyword">in</span> global context and not <span class="keyword">in</span> a block scope</span>
Object<span class="punctuation">.</span><span class="mark">defineProperty</span><span class="punctuation">(</span>typeof global <span class="punctuation">===</span> <span class="literal">"object"</span> ? global : window<span class="punctuation">,</span> <span class="literal">"<span class="mark">PI</span>"</span><span class="punctuation">,</span> <span class="punctuation">{</span>
value: <span class="literal">3</span><span class="punctuation">.</span><span class="literal">141593</span><span class="punctuation">,</span>
enumerable: true<span class="punctuation">,</span>
<span class="mark">writable: false</span><span class="punctuation">,</span>
<span class="mark">configurable: false</span>
<span class="punctuation">}</span><span class="punctuation">)</span>
PI <span class="punctuation">></span> <span class="literal">3</span><span class="punctuation">.</span><span class="literal">0</span><span class="semi">;</span></div>
<i class="icon fa fa-circle"></i>
<i class="icon fa fa-times-circle"></i>
</div>
</div>
<div id="BlockScopedVariables" class="showcase showcase_BlockScopedVariables"> <div class="title">Scoping</div>
<div class="subtitle">Block-Scoped Variables (局部变量)</div>
<div class="desc">Block-scoped variables (and constants) without hoisting.</div>
<div class="js es6">
<div class="title"><b>ECMAScript 6</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code"><span class="keyword">for</span> <span class="punctuation">(</span><span class="mark"><span class="keyword">let</span> i</span><span class="punctuation"> = </span><span class="literal">0</span><span class="punctuation">;</span> i <span class="punctuation"><</span> a<span class="punctuation">.</span>length<span class="punctuation">;</span> i<span class="punctuation">+</span><span class="punctuation">+</span><span class="punctuation">)</span> <span class="punctuation">{</span>
<span class="mark"><span class="keyword">let</span> x</span><span class="punctuation"> = </span>a<span class="punctuation">[</span>i<span class="punctuation">]</span><span class="semi">;</span>
<span class="ellipsis">…</span>
<span class="punctuation">}</span>
<span class="keyword">for</span> <span class="punctuation">(</span><span class="mark"><span class="keyword">let</span> i</span><span class="punctuation"> = </span><span class="literal">0</span><span class="punctuation">;</span> i <span class="punctuation"><</span> b<span class="punctuation">.</span>length<span class="punctuation">;</span> i<span class="punctuation">+</span><span class="punctuation">+</span><span class="punctuation">)</span> <span class="punctuation">{</span>
<span class="mark"><span class="keyword">let</span> y</span><span class="punctuation"> = </span>b<span class="punctuation">[</span>i<span class="punctuation">]</span><span class="semi">;</span>
<span class="ellipsis">…</span>
<span class="punctuation">}</span>
<span class="keyword">let</span> callbacks<span class="punctuation"> = </span><span class="punctuation">[</span><span class="punctuation">]</span><span class="semi">;</span>
<span class="keyword">for</span> <span class="punctuation">(</span><span class="mark"><span class="keyword">let</span></span> i<span class="punctuation"> = </span><span class="literal">0</span><span class="punctuation">;</span> i <span class="punctuation"><</span>= <span class="literal">2</span><span class="punctuation">;</span> i<span class="punctuation">+</span><span class="punctuation">+</span><span class="punctuation">)</span> <span class="punctuation">{</span>
callbacks<span class="punctuation">[</span>i<span class="punctuation">]</span><span class="punctuation"> = </span><span class="keyword">function</span> <span class="punctuation">(</span><span class="punctuation">)</span> <span class="punctuation">{</span> <span class="keyword">return</span> i <span class="punctuation">*</span> <span class="literal">2</span><span class="semi">;</span> <span class="punctuation">}</span><span class="semi">;</span>
<span class="punctuation">}</span>
callbacks<span class="punctuation">[</span><span class="literal">0</span><span class="punctuation">]</span><span class="punctuation">(</span><span class="punctuation">)</span> <span class="punctuation">===</span> <span class="literal">0</span><span class="semi">;</span>
callbacks<span class="punctuation">[</span><span class="literal">1</span><span class="punctuation">]</span><span class="punctuation">(</span><span class="punctuation">)</span> <span class="punctuation">===</span> <span class="literal">2</span><span class="semi">;</span>
callbacks<span class="punctuation">[</span><span class="literal">2</span><span class="punctuation">]</span><span class="punctuation">(</span><span class="punctuation">)</span> <span class="punctuation">===</span> <span class="literal">4</span><span class="semi">;</span>
</div>
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<div class="title"><b>ECMAScript 5</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code"><span class="mark"><span class="keyword">var</span> i<span class="punctuation">,</span> x<span class="punctuation">,</span> y</span><span class="semi">;</span>
<span class="keyword">for</span> <span class="punctuation">(</span>i<span class="punctuation"> = </span><span class="literal">0</span><span class="punctuation">;</span> i <span class="punctuation"><</span> a<span class="punctuation">.</span>length<span class="punctuation">;</span> i<span class="punctuation">+</span><span class="punctuation">+</span><span class="punctuation">)</span> <span class="punctuation">{</span>
x<span class="punctuation"> = </span>a<span class="punctuation">[</span>i<span class="punctuation">]</span><span class="semi">;</span>
<span class="ellipsis">…</span>
<span class="punctuation">}</span>
<span class="keyword">for</span> <span class="punctuation">(</span>i<span class="punctuation"> = </span><span class="literal">0</span><span class="punctuation">;</span> i <span class="punctuation"><</span> b<span class="punctuation">.</span>length<span class="punctuation">;</span> i<span class="punctuation">+</span><span class="punctuation">+</span><span class="punctuation">)</span> <span class="punctuation">{</span>
y<span class="punctuation"> = </span>b<span class="punctuation">[</span>i<span class="punctuation">]</span><span class="semi">;</span>
<span class="ellipsis">…</span>
<span class="punctuation">}</span>
<span class="keyword">var</span> callbacks<span class="punctuation"> = </span><span class="punctuation">[</span><span class="punctuation">]</span><span class="semi">;</span>
<span class="keyword">for</span> <span class="punctuation">(</span><span class="mark"><span class="keyword">var</span></span> i<span class="punctuation"> = </span><span class="literal">0</span><span class="punctuation">;</span> i <span class="punctuation"><</span>= <span class="literal">2</span><span class="punctuation">;</span> i<span class="punctuation">+</span><span class="punctuation">+</span><span class="punctuation">)</span> <span class="punctuation">{</span>
<span class="mark"><span class="punctuation">(</span><span class="keyword">function</span> <span class="punctuation">(</span>i<span class="punctuation">)</span> <span class="punctuation">{</span></span>
callbacks<span class="punctuation">[</span>i<span class="punctuation">]</span><span class="punctuation"> = </span><span class="keyword">function</span><span class="punctuation">(</span><span class="punctuation">)</span> <span class="punctuation">{</span> <span class="keyword">return</span> i <span class="punctuation">*</span> <span class="literal">2</span><span class="semi">;</span> <span class="punctuation">}</span><span class="semi">;</span>
<span class="mark"><span class="punctuation">}</span><span class="punctuation">)</span><span class="punctuation">(</span>i<span class="punctuation">)</span><span class="punctuation">;</span></span>
<span class="punctuation">}</span>
callbacks<span class="punctuation">[</span><span class="literal">0</span><span class="punctuation">]</span><span class="punctuation">(</span><span class="punctuation">)</span> <span class="punctuation">===</span> <span class="literal">0</span><span class="semi">;</span>
callbacks<span class="punctuation">[</span><span class="literal">1</span><span class="punctuation">]</span><span class="punctuation">(</span><span class="punctuation">)</span> <span class="punctuation">===</span> <span class="literal">2</span><span class="semi">;</span>
callbacks<span class="punctuation">[</span><span class="literal">2</span><span class="punctuation">]</span><span class="punctuation">(</span><span class="punctuation">)</span> <span class="punctuation">===</span> <span class="literal">4</span><span class="semi">;</span></div>
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</div>
<div id="BlockScopedFunctions" class="showcase showcase_BlockScopedFunctions"> <div class="title">Scoping</div>
<div class="subtitle">Block-Scoped Functions (局部作用域)</div>
<div class="desc">Block-scoped function definitions.</div>
<div class="js es6">
<div class="title"><b>ECMAScript 6</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code"><span class="punctuation">{</span>
<span class="keyword">function</span> foo <span class="punctuation">(</span><span class="punctuation">)</span> <span class="punctuation">{</span> <span class="keyword">return</span> <span class="literal">1</span><span class="semi">;</span> <span class="punctuation">}</span>
foo<span class="punctuation">(</span><span class="punctuation">)</span> <span class="punctuation">===</span> <span class="literal">1</span><span class="semi">;</span>
<span class="punctuation">{</span>
<span class="keyword">function</span> <span class="mark">foo</span> <span class="punctuation">(</span><span class="punctuation">)</span> <span class="punctuation">{</span> <span class="keyword">return</span> <span class="mark"><span class="literal">2</span></span><span class="semi">;</span> <span class="punctuation">}</span>
<span class="mark">foo</span><span class="punctuation">(</span><span class="punctuation">)</span> <span class="punctuation">===</span> <span class="mark"><span class="literal">2</span></span><span class="semi">;</span>
<span class="punctuation">}</span>
foo<span class="punctuation">(</span><span class="punctuation">)</span> <span class="punctuation">===</span> <span class="literal">1</span><span class="semi">;</span>
<span class="punctuation">}</span>
</div>
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<div class="title"><b>ECMAScript 5</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code"><span class="comment">// only <span class="keyword">in</span> ES<span class="literal">5</span> with the help <span class="keyword">of</span> block<span class="punctuation">-</span>scope emulating</span><span class="comment">
// <span class="keyword">function</span> scopes and <span class="keyword">function</span> expressions</span>
<span class="punctuation">(</span><span class="keyword">function</span> <span class="punctuation">(</span><span class="punctuation">)</span> <span class="punctuation">{</span>
<span class="keyword">var</span> foo<span class="punctuation"> = </span><span class="keyword">function</span> <span class="punctuation">(</span><span class="punctuation">)</span> <span class="punctuation">{</span> <span class="keyword">return</span> <span class="literal">1</span><span class="semi">;</span> <span class="punctuation">}</span>
foo<span class="punctuation">(</span><span class="punctuation">)</span> <span class="punctuation">===</span> <span class="literal">1</span><span class="semi">;</span>
<span class="mark"><span class="punctuation">(</span><span class="keyword">function</span> <span class="punctuation">(</span><span class="punctuation">)</span> <span class="punctuation">{</span></span>
<span class="keyword">var</span> <span class="mark">foo</span><span class="punctuation"> = </span><span class="keyword">function</span> <span class="punctuation">(</span><span class="punctuation">)</span> <span class="punctuation">{</span> <span class="keyword">return</span> <span class="mark"><span class="literal">2</span></span><span class="semi">;</span> <span class="punctuation">}</span>
<span class="mark">foo</span><span class="punctuation">(</span><span class="punctuation">)</span> <span class="punctuation">===</span> <span class="mark"><span class="literal">2</span></span><span class="semi">;</span>
<span class="mark"><span class="punctuation">}</span><span class="punctuation">)</span><span class="punctuation">(</span><span class="punctuation">)</span><span class="punctuation">;</span></span>
foo<span class="punctuation">(</span><span class="punctuation">)</span> <span class="punctuation">===</span> <span class="literal">1</span><span class="semi">;</span>
<span class="punctuation">}</span><span class="punctuation">)</span><span class="punctuation">(</span><span class="punctuation">)</span><span class="semi">;</span></div>
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</div>
<div id="ExpressionBodies" class="showcase showcase_ExpressionBodies"> <div class="title">Arrow Functions (箭头函数)</div>
<div class="subtitle">Expression Bodies (表达式)</div>
<div class="desc">More expressive closure syntax.</div>
<div class="js es6">
<div class="title"><b>ECMAScript 6</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code">odds <span class="punctuation"> = </span>evens<span class="punctuation">.</span>map<span class="punctuation">(</span><span class="mark">v <span class="punctuation">=></span></span> v <span class="punctuation">+</span> <span class="literal">1</span><span class="punctuation">)</span><span class="semi">;</span>
pairs<span class="punctuation"> = </span>evens<span class="punctuation">.</span>map<span class="punctuation">(</span><span class="mark">v <span class="punctuation">=></span> <span class="punctuation">(</span></span><span class="punctuation">{</span> even: v<span class="punctuation">,</span> odd: v <span class="punctuation">+</span> <span class="literal">1</span> <span class="punctuation">}</span><span class="mark"><span class="punctuation">)</span></span><span class="punctuation">)</span><span class="semi">;</span>
nums <span class="punctuation"> = </span>evens<span class="punctuation">.</span>map<span class="punctuation">(</span><span class="mark"><span class="punctuation">(</span>v<span class="punctuation">,</span> i<span class="punctuation">)</span> <span class="punctuation">=></span></span> v <span class="punctuation">+</span> i<span class="punctuation">)</span><span class="semi">;</span>
</div>
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<div class="title"><b>ECMAScript 5</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code">odds <span class="punctuation"> = </span>evens<span class="punctuation">.</span>map<span class="punctuation">(</span><span class="mark"><span class="keyword">function</span> <span class="punctuation">(</span>v<span class="punctuation">)</span> <span class="punctuation">{</span> <span class="keyword">return</span></span> v <span class="punctuation">+</span> <span class="literal">1</span><span class="semi">;</span> <span class="mark"><span class="punctuation">}</span></span><span class="punctuation">)</span><span class="semi">;</span>
pairs<span class="punctuation"> = </span>evens<span class="punctuation">.</span>map<span class="punctuation">(</span><span class="mark"><span class="keyword">function</span> <span class="punctuation">(</span>v<span class="punctuation">)</span> <span class="punctuation">{</span> <span class="keyword">return</span></span> <span class="punctuation">{</span> even: v<span class="punctuation">,</span> odd: v <span class="punctuation">+</span> <span class="literal">1</span> <span class="punctuation">}</span><span class="semi">;</span> <span class="mark"><span class="punctuation">}</span></span><span class="punctuation">)</span><span class="semi">;</span>
nums <span class="punctuation"> = </span>evens<span class="punctuation">.</span>map<span class="punctuation">(</span><span class="mark"><span class="keyword">function</span> <span class="punctuation">(</span>v<span class="punctuation">,</span> i<span class="punctuation">)</span> <span class="punctuation">{</span> <span class="keyword">return</span></span> v <span class="punctuation">+</span> i<span class="semi">;</span> <span class="mark"><span class="punctuation">}</span></span><span class="punctuation">)</span><span class="semi">;</span></div>
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</div>
<div id="StatementBodies" class="showcase showcase_StatementBodies"> <div class="title">Arrow Functions (箭头函数)</div>
<div class="subtitle">Statement Bodies (声明式)</div>
<div class="desc">More expressive closure syntax.</div>
<div class="js es6">
<div class="title"><b>ECMAScript 6</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code">nums<span class="punctuation">.</span>forEach<span class="punctuation">(</span><span class="mark">v <span class="punctuation">=></span> <span class="punctuation">{</span></span>
<span class="keyword">if</span> <span class="punctuation">(</span>v <span class="punctuation">%</span> <span class="literal">5</span> <span class="punctuation">===</span> <span class="literal">0</span><span class="punctuation">)</span>
fives<span class="punctuation">.</span>push<span class="punctuation">(</span>v<span class="punctuation">)</span><span class="semi">;</span>
<span class="mark"><span class="punctuation">}</span></span><span class="punctuation">)</span>
</div>
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<div class="title"><b>ECMAScript 5</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code">nums<span class="punctuation">.</span>forEach<span class="punctuation">(</span><span class="mark"><span class="keyword">function</span> <span class="punctuation">(</span>v<span class="punctuation">)</span> <span class="punctuation">{</span></span>
<span class="keyword">if</span> <span class="punctuation">(</span>v <span class="punctuation">%</span> <span class="literal">5</span> <span class="punctuation">===</span> <span class="literal">0</span><span class="punctuation">)</span>
fives<span class="punctuation">.</span>push<span class="punctuation">(</span>v<span class="punctuation">)</span><span class="semi">;</span>
<span class="mark"><span class="punctuation">}</span></span><span class="punctuation">)</span><span class="semi">;</span></div>
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</div>
<div id="Lexicalthis" class="showcase showcase_Lexicalthis"> <div class="title">Arrow Functions (箭头函数)</div>
<div class="subtitle">Lexical <code>this</code> (绑定作用域)</div>
<div class="desc">More intuitive handling of current object context.</div>
<div class="js es6">
<div class="title"><b>ECMAScript 6</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code"><span class="mark"><span class="keyword">this</span></span><span class="punctuation">.</span>nums<span class="punctuation">.</span>forEach<span class="punctuation">(</span><span class="mark"><span class="punctuation">(</span>v<span class="punctuation">)</span> <span class="punctuation">=></span></span> <span class="punctuation">{</span>
<span class="keyword">if</span> <span class="punctuation">(</span>v <span class="punctuation">%</span> <span class="literal">5</span> <span class="punctuation">===</span> <span class="literal">0</span><span class="punctuation">)</span>
<span class="mark"><span class="keyword">this</span></span><span class="punctuation">.</span>fives<span class="punctuation">.</span>push<span class="punctuation">(</span>v<span class="punctuation">)</span><span class="semi">;</span>
<span class="punctuation">}</span><span class="punctuation">)</span><span class="semi">;</span>
</div>
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<div class="arrow"><i class="fa fa-caret-up"></i><i class="fa fa-caret-down"></i></div><div class="js es5">
<div class="title"><b>ECMAScript 5</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code"><span class="comment">// variant <span class="literal">1</span></span>
<span class="keyword">var</span> <span class="mark">self</span><span class="punctuation"> = </span><span class="mark"><span class="keyword">this</span></span><span class="semi">;</span>
<span class="mark"><span class="keyword">this</span></span><span class="punctuation">.</span>nums<span class="punctuation">.</span>forEach<span class="punctuation">(</span><span class="mark"><span class="keyword">function</span> <span class="punctuation">(</span>v<span class="punctuation">)</span></span> <span class="punctuation">{</span>
<span class="keyword">if</span> <span class="punctuation">(</span>v <span class="punctuation">%</span> <span class="literal">5</span> <span class="punctuation">===</span> <span class="literal">0</span><span class="punctuation">)</span>
<span class="mark">self</span><span class="punctuation">.</span>fives<span class="punctuation">.</span>push<span class="punctuation">(</span>v<span class="punctuation">)</span><span class="semi">;</span>
<span class="punctuation">}</span><span class="punctuation">)</span><span class="semi">;</span>
<span class="comment">
// variant <span class="literal">2</span></span>
<span class="mark"><span class="keyword">this</span></span><span class="punctuation">.</span>nums<span class="punctuation">.</span>forEach<span class="punctuation">(</span><span class="mark"><span class="keyword">function</span> <span class="punctuation">(</span>v<span class="punctuation">)</span></span> <span class="punctuation">{</span>
<span class="keyword">if</span> <span class="punctuation">(</span>v <span class="punctuation">%</span> <span class="literal">5</span> <span class="punctuation">===</span> <span class="literal">0</span><span class="punctuation">)</span>
<span class="mark"><span class="keyword">this</span></span><span class="punctuation">.</span>fives<span class="punctuation">.</span>push<span class="punctuation">(</span>v<span class="punctuation">)</span><span class="semi">;</span>
<span class="punctuation">}</span><span class="punctuation">,</span> <span class="mark"><span class="keyword">this</span></span><span class="punctuation">)</span><span class="semi">;</span>
<span class="comment">
// variant <span class="literal">3</span> <span class="punctuation">(</span>since ECMAScript <span class="literal">5</span><span class="punctuation">.</span><span class="literal">1</span> only<span class="punctuation">)</span></span>
<span class="mark"><span class="keyword">this</span></span><span class="punctuation">.</span>nums<span class="punctuation">.</span>forEach<span class="punctuation">(</span><span class="mark"><span class="keyword">function</span> <span class="punctuation">(</span>v<span class="punctuation">)</span></span> <span class="punctuation">{</span>
<span class="keyword">if</span> <span class="punctuation">(</span>v <span class="punctuation">%</span> <span class="literal">5</span> <span class="punctuation">===</span> <span class="literal">0</span><span class="punctuation">)</span>
<span class="mark"><span class="keyword">this</span></span><span class="punctuation">.</span>fives<span class="punctuation">.</span>push<span class="punctuation">(</span>v<span class="punctuation">)</span><span class="semi">;</span>
<span class="punctuation">}</span><span class="mark"><span class="punctuation">.</span>bind<span class="punctuation">(</span><span class="keyword">this</span><span class="punctuation">)</span></span><span class="punctuation">)</span><span class="semi">;</span></div>
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</div>
<div id="DefaultParameterValues" class="showcase showcase_DefaultParameterValues"> <div class="title">Extended Parameter Handling (扩展函数参数)</div>
<div class="subtitle">Default Parameter Values (参数默认值)</div>
<div class="desc">Simple and intuitive default values for function parameters.</div>
<div class="js es6">
<div class="title"><b>ECMAScript 6</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code"><span class="keyword">function</span> f <span class="punctuation">(</span>x<span class="punctuation">,</span> y <span class="mark">= <span class="literal">7</span></span><span class="punctuation">,</span> z <span class="mark">= <span class="literal">42</span></span><span class="punctuation">)</span> <span class="punctuation">{</span>
<span class="keyword">return</span> x <span class="punctuation">+</span> y <span class="punctuation">+</span> z<span class="semi">;</span>
<span class="punctuation">}</span>
f<span class="punctuation">(</span><span class="literal">1</span><span class="punctuation">)</span> <span class="punctuation">===</span> <span class="literal">50</span><span class="semi">;</span>
</div>
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</div>
<div class="arrow"><i class="fa fa-caret-up"></i><i class="fa fa-caret-down"></i></div><div class="js es5">
<div class="title"><b>ECMAScript 5</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code"><span class="keyword">function</span> f <span class="punctuation">(</span>x<span class="punctuation">,</span> y<span class="punctuation">,</span> z<span class="punctuation">)</span> <span class="punctuation">{</span>
<span class="mark"><span class="keyword">if</span> <span class="punctuation">(</span>y <span class="punctuation">===</span> undefined<span class="punctuation">)</span></span>
<span class="mark">y<span class="punctuation"> = </span><span class="literal">7</span></span><span class="semi">;</span>
<span class="mark"><span class="keyword">if</span> <span class="punctuation">(</span>z <span class="punctuation">===</span> undefined<span class="punctuation">)</span></span>
<span class="mark">z<span class="punctuation"> = </span><span class="literal">42</span></span><span class="semi">;</span>
<span class="keyword">return</span> x <span class="punctuation">+</span> y <span class="punctuation">+</span> z<span class="semi">;</span>
<span class="punctuation">}</span><span class="semi">;</span>
f<span class="punctuation">(</span><span class="literal">1</span><span class="punctuation">)</span> <span class="punctuation">===</span> <span class="literal">50</span><span class="semi">;</span></div>
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</div>
</div>
<div id="RestParameterrest" class="showcase showcase_RestParameterrest"> <div class="title">Extended Parameter Handling (扩展函数参数)</div>
<div class="subtitle">Rest Parameter (rest 参数)</div>
<div class="desc">Aggregation of remaining arguments into single parameter of variadic functions.</div>
<div class="js es6">
<div class="title"><b>ECMAScript 6</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code"><span class="keyword">function</span> f <span class="punctuation">(</span>x<span class="punctuation">,</span> y<span class="punctuation">,</span> <span class="mark"><span class="punctuation">.</span><span class="punctuation">.</span><span class="punctuation">.</span>a</span><span class="punctuation">)</span> <span class="punctuation">{</span>
<span class="keyword">return</span> <span class="punctuation">(</span>x <span class="punctuation">+</span> y<span class="punctuation">)</span> <span class="punctuation">*</span> a<span class="punctuation">.</span>length<span class="semi">;</span>
<span class="punctuation">}</span>
f<span class="punctuation">(</span><span class="literal">1</span><span class="punctuation">,</span> <span class="literal">2</span><span class="punctuation">,</span> <span class="mark"><span class="literal">"hello"</span><span class="punctuation">,</span> true<span class="punctuation">,</span> <span class="literal">7</span></span><span class="punctuation">)</span> <span class="punctuation">===</span> <span class="literal">9</span><span class="semi">;</span>
</div>
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<div class="title"><b>ECMAScript 5</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code"><span class="keyword">function</span> f <span class="punctuation">(</span>x<span class="punctuation">,</span> y<span class="punctuation">)</span> <span class="punctuation">{</span>
<span class="mark"><span class="keyword">var</span> a<span class="punctuation"> = </span>Array<span class="punctuation">.</span>prototype<span class="punctuation">.</span>slice<span class="punctuation">.</span>call<span class="punctuation">(</span>arguments<span class="punctuation">,</span> <span class="literal">2</span><span class="punctuation">)</span></span><span class="semi">;</span>
<span class="keyword">return</span> <span class="punctuation">(</span>x <span class="punctuation">+</span> y<span class="punctuation">)</span> <span class="punctuation">*</span> a<span class="punctuation">.</span>length<span class="semi">;</span>
<span class="punctuation">}</span><span class="semi">;</span>
f<span class="punctuation">(</span><span class="literal">1</span><span class="punctuation">,</span> <span class="literal">2</span><span class="punctuation">,</span> <span class="mark"><span class="literal">"hello"</span><span class="punctuation">,</span> true<span class="punctuation">,</span> <span class="literal">7</span></span><span class="punctuation">)</span> <span class="punctuation">===</span> <span class="literal">9</span><span class="semi">;</span></div>
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</div>
<div id="SpreadOperator" class="showcase showcase_SpreadOperator"> <div class="title">Extended Parameter Handling (扩展函数参数)</div>
<div class="subtitle">Spread Operator (扩展参数)</div>
<div class="desc">Spreading of elements of an iterable collection (like an array or even
a string) into both literal elements and individual function parameters.</div>
<div class="js es6">
<div class="title"><b>ECMAScript 6</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code"><span class="keyword">var</span> params<span class="punctuation"> = </span><span class="punctuation">[</span> <span class="literal">"hello"</span><span class="punctuation">,</span> true<span class="punctuation">,</span> <span class="literal">7</span> <span class="punctuation">]</span><span class="semi">;</span>
<span class="keyword">var</span> other<span class="punctuation"> = </span><span class="punctuation">[</span> <span class="literal">1</span><span class="punctuation">,</span> <span class="literal">2</span><span class="punctuation">,</span> <span class="mark"><span class="punctuation">.</span><span class="punctuation">.</span><span class="punctuation">.</span>params</span> <span class="punctuation">]</span><span class="semi">;</span><span class="comment"> // <span class="punctuation">[</span> <span class="literal">1</span><span class="punctuation">,</span> <span class="literal">2</span><span class="punctuation">,</span> <span class="literal">"hello"</span><span class="punctuation">,</span> true<span class="punctuation">,</span> <span class="literal">7</span> <span class="punctuation">]</span></span>
<span class="keyword">function</span> f <span class="punctuation">(</span>x<span class="punctuation">,</span> y<span class="punctuation">,</span> <span class="punctuation">.</span><span class="punctuation">.</span><span class="punctuation">.</span>a<span class="punctuation">)</span> <span class="punctuation">{</span>
<span class="keyword">return</span> <span class="punctuation">(</span>x <span class="punctuation">+</span> y<span class="punctuation">)</span> <span class="punctuation">*</span> a<span class="punctuation">.</span>length<span class="semi">;</span>
<span class="punctuation">}</span>
f<span class="punctuation">(</span><span class="literal">1</span><span class="punctuation">,</span> <span class="literal">2</span><span class="punctuation">,</span> <span class="mark"><span class="punctuation">.</span><span class="punctuation">.</span><span class="punctuation">.</span>params</span><span class="punctuation">)</span> <span class="punctuation">===</span> <span class="literal">9</span><span class="semi">;</span>
<span class="keyword">var</span> str<span class="punctuation"> = </span><span class="literal">"foo"</span><span class="semi">;</span>
<span class="keyword">var</span> chars<span class="punctuation"> = </span><span class="punctuation">[</span> <span class="mark"><span class="punctuation">.</span><span class="punctuation">.</span><span class="punctuation">.</span>str</span> <span class="punctuation">]</span><span class="semi">;</span><span class="comment"> // <span class="punctuation">[</span> <span class="literal">"f"</span><span class="punctuation">,</span> <span class="literal">"o"</span><span class="punctuation">,</span> <span class="literal">"o"</span> <span class="punctuation">]</span></span>
</div>
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<div class="title"><b>ECMAScript 5</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code"><span class="keyword">var</span> params<span class="punctuation"> = </span><span class="punctuation">[</span> <span class="literal">"hello"</span><span class="punctuation">,</span> true<span class="punctuation">,</span> <span class="literal">7</span> <span class="punctuation">]</span><span class="semi">;</span>
<span class="keyword">var</span> other<span class="punctuation"> = </span><span class="punctuation">[</span> <span class="literal">1</span><span class="punctuation">,</span> <span class="literal">2</span> <span class="punctuation">]</span><span class="punctuation">.</span><span class="mark">concat<span class="punctuation">(</span>params<span class="punctuation">)</span></span><span class="semi">;</span><span class="comment"> // <span class="punctuation">[</span> <span class="literal">1</span><span class="punctuation">,</span> <span class="literal">2</span><span class="punctuation">,</span> <span class="literal">"hello"</span><span class="punctuation">,</span> true<span class="punctuation">,</span> <span class="literal">7</span> <span class="punctuation">]</span></span>
<span class="keyword">function</span> f <span class="punctuation">(</span>x<span class="punctuation">,</span> y<span class="punctuation">)</span> <span class="punctuation">{</span>
<span class="keyword">var</span> a<span class="punctuation"> = </span>Array<span class="punctuation">.</span>prototype<span class="punctuation">.</span>slice<span class="punctuation">.</span>call<span class="punctuation">(</span>arguments<span class="punctuation">,</span> <span class="literal">2</span><span class="punctuation">)</span><span class="semi">;</span>
<span class="keyword">return</span> <span class="punctuation">(</span>x <span class="punctuation">+</span> y<span class="punctuation">)</span> <span class="punctuation">*</span> a<span class="punctuation">.</span>length<span class="semi">;</span>
<span class="punctuation">}</span><span class="semi">;</span>
f<span class="mark"><span class="punctuation">.</span>apply</span><span class="punctuation">(</span><span class="mark">undefined<span class="punctuation">,</span> <span class="punctuation">[</span></span> <span class="literal">1</span><span class="punctuation">,</span> <span class="literal">2</span> <span class="mark"><span class="punctuation">]</span><span class="punctuation">.</span>concat<span class="punctuation">(</span>params<span class="punctuation">)</span></span><span class="punctuation">)</span> <span class="punctuation">===</span> <span class="literal">9</span><span class="semi">;</span>
<span class="keyword">var</span> str<span class="punctuation"> = </span><span class="literal">"foo"</span><span class="semi">;</span>
<span class="keyword">var</span> chars<span class="punctuation"> = </span>str<span class="punctuation">.</span>split<span class="punctuation">(</span><span class="literal">""</span><span class="punctuation">)</span><span class="semi">;</span><span class="comment"> // <span class="punctuation">[</span> <span class="literal">"f"</span><span class="punctuation">,</span> <span class="literal">"o"</span><span class="punctuation">,</span> <span class="literal">"o"</span> <span class="punctuation">]</span></span></div>
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</div>
<div id="StringInterpolation" class="showcase showcase_StringInterpolation"> <div class="title">Template Literals (模版字面量)</div>
<div class="subtitle">String Interpolation (字符串变量)</div>
<div class="desc">Intuitive expression interpolation for single-line and multi-line strings.
(Notice: don't be confused, Template Literals were originally named
"Template Strings" in the drafts of the ECMAScript 6 language specification)</div>
<div class="js es6">
<div class="title"><b>ECMAScript 6</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code"><span class="keyword">var</span> customer<span class="punctuation"> = </span><span class="punctuation">{</span> name: <span class="literal">"Foo"</span> <span class="punctuation">}</span><span class="semi">;</span>
<span class="keyword">var</span> card<span class="punctuation"> = </span><span class="punctuation">{</span> amount: <span class="literal">7</span><span class="punctuation">,</span> product: <span class="literal">"Bar"</span><span class="punctuation">,</span> unitprice: <span class="literal">42</span> <span class="punctuation">}</span><span class="semi">;</span>
<span class="keyword">var</span> message<span class="punctuation"> = </span><span class="mark"><span class="literal">`</span>Hello <span class="mark">$<span class="punctuation">{</span>customer<span class="punctuation">.</span>name<span class="punctuation">}</span></span><span class="punctuation">,</span>
want to buy <span class="mark">$<span class="punctuation">{</span>card<span class="punctuation">.</span>amount<span class="punctuation">}</span> $<span class="punctuation">{</span>card<span class="punctuation">.</span>product<span class="punctuation">}</span></span> <span class="keyword">for</span>
a total <span class="keyword">of</span> <span class="mark">$<span class="punctuation">{</span>card<span class="punctuation">.</span>amount <span class="punctuation">*</span> card<span class="punctuation">.</span>unitprice<span class="punctuation">}</span></span> bucks?<span class="mark">`</span></span><span class="semi">;</span>
</div>
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<div class="title"><b>ECMAScript 5</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code"><span class="keyword">var</span> customer<span class="punctuation"> = </span><span class="punctuation">{</span> name: <span class="literal">"Foo"</span> <span class="punctuation">}</span><span class="semi">;</span>
<span class="keyword">var</span> card<span class="punctuation"> = </span><span class="punctuation">{</span> amount: <span class="literal">7</span><span class="punctuation">,</span> product: <span class="literal">"Bar"</span><span class="punctuation">,</span> unitprice: <span class="literal">42</span> <span class="punctuation">}</span><span class="semi">;</span>
<span class="keyword">var</span> message<span class="punctuation"> = </span><span class="mark"><span class="literal">"</span>Hello "</span><span class="mark"> <span class="punctuation">+</span> customer<span class="punctuation">.</span>name <span class="punctuation">+</span> </span><span class="literal">"<span class="punctuation">,</span>\n"</span> <span class="punctuation">+</span>
<span class="literal">"want to buy "</span><span class="mark"> <span class="punctuation">+</span> card<span class="punctuation">.</span>amount <span class="punctuation">+</span> </span><span class="literal">" "</span><span class="mark"> <span class="punctuation">+</span> card<span class="punctuation">.</span>product <span class="punctuation">+</span> </span><span class="literal">" <span class="keyword">for</span>\n"</span> <span class="punctuation">+</span>
<span class="literal">"a total <span class="keyword">of</span> "</span><span class="mark"> <span class="punctuation">+</span> <span class="punctuation">(</span>card<span class="punctuation">.</span>amount <span class="punctuation">*</span> card<span class="punctuation">.</span>unitprice<span class="punctuation">)</span> <span class="punctuation">+</span> </span><span class="literal">" bucks?<span class="mark">"</span></span><span class="semi">;</span></div>
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</div>
<div id="PropertyShorthand" class="showcase showcase_PropertyShorthand"> <div class="title">Enhanced Object Properties (增强对象属性)</div>
<div class="subtitle">Property Shorthand (属性缩写)</div>
<div class="desc">Shorter syntax for common object property definition idiom.</div>
<div class="js es6">
<div class="title"><b>ECMAScript 6</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code">obj<span class="punctuation"> = </span><span class="punctuation">{</span> <span class="mark">x</span><span class="punctuation">,</span> <span class="mark">y</span> <span class="punctuation">}</span><span class="semi">;</span>
</div>
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<div class="title"><b>ECMAScript 5</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code">obj<span class="punctuation"> = </span><span class="punctuation">{</span> <span class="mark">x: x</span><span class="punctuation">,</span> <span class="mark">y: y</span> <span class="punctuation">}</span><span class="semi">;</span></div>
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</div>
<div id="ComputedPropertyNames" class="showcase showcase_ComputedPropertyNames"> <div class="title">Enhanced Object Properties (增强对象属性)</div>
<div class="subtitle">Computed Property Names (计算属性名)</div>
<div class="desc">Support for computed names in object property definitions.</div>
<div class="js es6">
<div class="title"><b>ECMAScript 6</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code"><span class="keyword">let</span> obj<span class="punctuation"> = </span><span class="punctuation">{</span>
foo: <span class="literal">"bar"</span><span class="punctuation">,</span>
<span class="mark"><span class="punctuation">[</span></span> <span class="literal">"baz"</span> <span class="punctuation">+</span> quux<span class="punctuation">(</span><span class="punctuation">)</span> <span class="mark"><span class="punctuation">]</span>:</span> <span class="literal">42</span>
<span class="punctuation">}</span><span class="semi">;</span>
</div>
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<div class="title"><b>ECMAScript 5</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code"><span class="keyword">var</span> obj<span class="punctuation"> = </span><span class="punctuation">{</span>
foo: <span class="literal">"bar"</span>
<span class="punctuation">}</span><span class="semi">;</span>
<span class="mark">obj<span class="punctuation">[</span></span> <span class="literal">"baz"</span> <span class="punctuation">+</span> quux<span class="punctuation">(</span><span class="punctuation">)</span> <span class="mark"><span class="punctuation">]</span> =</span> <span class="literal">42</span><span class="semi">;</span></div>
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</div>
<div id="MethodProperties" class="showcase showcase_MethodProperties"> <div class="title">Enhanced Object Properties (增强对象属性)</div>
<div class="subtitle">Method Properties (方法)</div>
<div class="desc">Support for method notation in object property definitions,
for both regular functions and generator functions.</div>
<div class="js es6">
<div class="title"><b>ECMAScript 6</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code">obj<span class="punctuation"> = </span><span class="punctuation">{</span>
<span class="mark">foo <span class="punctuation">(</span>a<span class="punctuation">,</span> b<span class="punctuation">)</span></span> <span class="punctuation">{</span>
<span class="ellipsis">…</span>
<span class="punctuation">}</span><span class="punctuation">,</span>
<span class="mark">bar <span class="punctuation">(</span>x<span class="punctuation">,</span> y<span class="punctuation">)</span></span> <span class="punctuation">{</span>
<span class="ellipsis">…</span>
<span class="punctuation">}</span><span class="punctuation">,</span>
<span class="mark"><span class="punctuation">*</span>quux <span class="punctuation">(</span>x<span class="punctuation">,</span> y<span class="punctuation">)</span></span> <span class="punctuation">{</span>
<span class="ellipsis">…</span>
<span class="punctuation">}</span>
<span class="punctuation">}</span><span class="semi">;</span>
</div>
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</div>
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<div class="title"><b>ECMAScript 5</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code">obj<span class="punctuation"> = </span><span class="punctuation">{</span>
foo<span class="mark">: <span class="keyword">function</span></span> <span class="punctuation">(</span>a<span class="punctuation">,</span> b<span class="punctuation">)</span> <span class="punctuation">{</span>
<span class="ellipsis">…</span>
<span class="punctuation">}</span><span class="punctuation">,</span>
bar<span class="mark">: <span class="keyword">function</span></span> <span class="punctuation">(</span>x<span class="punctuation">,</span> y<span class="punctuation">)</span> <span class="punctuation">{</span>
<span class="ellipsis">…</span>
<span class="punctuation">}</span><span class="punctuation">,</span>
<span class="comment"> // quux: no equivalent <span class="keyword">in</span> ES<span class="literal">5</span></span>
<span class="ellipsis">…</span>
<span class="punctuation">}</span><span class="semi">;</span></div>
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</div>
<div id="ArrayMatching" class="showcase showcase_ArrayMatching"> <div class="title">Destructuring Assignment (解构赋值)</div>
<div class="subtitle">Array Matching (数组)</div>
<div class="desc">Intuitive and flexible destructuring of Arrays into individual variables during assignment.</div>
<div class="js es6">
<div class="title"><b>ECMAScript 6</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code"><span class="keyword">var</span> list<span class="punctuation"> = </span><span class="punctuation">[</span> <span class="literal">1</span><span class="punctuation">,</span> <span class="literal">2</span><span class="punctuation">,</span> <span class="literal">3</span> <span class="punctuation">]</span><span class="semi">;</span>
<span class="keyword">var</span> <span class="mark"><span class="punctuation">[</span> a<span class="punctuation">,</span> <span class="punctuation">,</span> b <span class="punctuation">]</span><span class="punctuation"> = </span>list</span><span class="semi">;</span>
<span class="punctuation">[</span> <span class="mark">b<span class="punctuation">,</span> a</span> <span class="punctuation">]</span><span class="punctuation"> = </span><span class="punctuation">[</span> <span class="mark">a<span class="punctuation">,</span> b</span> <span class="punctuation">]</span><span class="semi">;</span>
</div>
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<div class="title"><b>ECMAScript 5</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code"><span class="keyword">var</span> list<span class="punctuation"> = </span><span class="punctuation">[</span> <span class="literal">1</span><span class="punctuation">,</span> <span class="literal">2</span><span class="punctuation">,</span> <span class="literal">3</span> <span class="punctuation">]</span><span class="semi">;</span>
<span class="keyword">var</span> <span class="mark">a<span class="punctuation"> = </span>list<span class="punctuation">[</span><span class="literal">0</span><span class="punctuation">]</span></span><span class="punctuation">,</span> <span class="mark">b<span class="punctuation"> = </span>list<span class="punctuation">[</span><span class="literal">2</span><span class="punctuation">]</span></span><span class="semi">;</span>
<span class="keyword">var</span> <span class="mark">tmp<span class="punctuation"> = </span>a</span><span class="punctuation">;</span> <span class="mark">a<span class="punctuation"> = </span>b</span><span class="punctuation">;</span> <span class="mark">b<span class="punctuation"> = </span>tmp</span><span class="semi">;</span></div>
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</div>
</div>
<div id="ObjectMatchingShorthandNotation" class="showcase showcase_ObjectMatchingShorthandNotation"> <div class="title">Destructuring Assignment (解构赋值)</div>
<div class="subtitle">Object Matching, Shorthand Notation (对象，简写)</div>
<div class="desc">Intuitive and flexible destructuring of Objects into individual variables during assignment.</div>
<div class="js es6">
<div class="title"><b>ECMAScript 6</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code"><span class="keyword">var</span> <span class="mark"><span class="punctuation">{</span> op<span class="punctuation">,</span> lhs<span class="punctuation">,</span> rhs <span class="punctuation">}</span></span><span class="punctuation"> = </span>getASTNode<span class="punctuation">(</span><span class="punctuation">)</span><span class="semi">;</span>
</div>
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</div>
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<div class="title"><b>ECMAScript 5</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code"><span class="keyword">var</span> <span class="mark">tmp</span><span class="punctuation"> = </span>getASTNode<span class="punctuation">(</span><span class="punctuation">)</span><span class="semi">;</span>
<span class="keyword">var</span> <span class="mark">op <span class="punctuation"> = </span>tmp<span class="punctuation">.</span>op</span><span class="semi">;</span>
<span class="keyword">var</span> <span class="mark">lhs<span class="punctuation"> = </span>tmp<span class="punctuation">.</span>lhs</span><span class="semi">;</span>
<span class="keyword">var</span> <span class="mark">rhs<span class="punctuation"> = </span>tmp<span class="punctuation">.</span>rhs</span><span class="semi">;</span></div>
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</div>
</div>
<div id="ObjectMatchingDeepMatching" class="showcase showcase_ObjectMatchingDeepMatching"> <div class="title">Destructuring Assignment (解构赋值)</div>
<div class="subtitle">Object Matching, Deep Matching (嵌套匹配)</div>
<div class="desc">Intuitive and flexible destructuring of Objects into individual variables during assignment.</div>
<div class="js es6">
<div class="title"><b>ECMAScript 6</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code"><span class="keyword">var</span> <span class="punctuation">{</span> op: a<span class="punctuation">,</span> <span class="mark">lhs: <span class="punctuation">{</span> op: b <span class="punctuation">}</span></span><span class="punctuation">,</span> rhs: c <span class="punctuation">}</span><span class="punctuation"> = </span>getASTNode<span class="punctuation">(</span><span class="punctuation">)</span><span class="semi">;</span>
</div>
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</div>
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<div class="title"><b>ECMAScript 5</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code"><span class="keyword">var</span> tmp<span class="punctuation"> = </span>getASTNode<span class="punctuation">(</span><span class="punctuation">)</span><span class="semi">;</span>
<span class="keyword">var</span> a<span class="punctuation"> = </span>tmp<span class="punctuation">.</span>op<span class="semi">;</span>
<span class="keyword">var</span> <span class="mark">b<span class="punctuation"> = </span>tmp<span class="punctuation">.</span>lhs<span class="punctuation">.</span>op</span><span class="semi">;</span>
<span class="keyword">var</span> c<span class="punctuation"> = </span>tmp<span class="punctuation">.</span>rhs<span class="semi">;</span></div>
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</div>
<div id="ObjectAndArrayMatchingDefaultValues" class="showcase showcase_ObjectAndArrayMatchingDefaultValues"> <div class="title">Destructuring Assignment (解构赋值)</div>
<div class="subtitle">Object And Array Matching, Default Values (默认值)</div>
<div class="desc">Simple and intuitive default values for destructuring of Objects and Arrays.</div>
<div class="js es6">
<div class="title"><b>ECMAScript 6</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code"><span class="keyword">var</span> obj<span class="punctuation"> = </span><span class="punctuation">{</span> a: <span class="literal">1</span> <span class="punctuation">}</span><span class="semi">;</span>
<span class="keyword">var</span> list<span class="punctuation"> = </span><span class="punctuation">[</span> <span class="literal">1</span> <span class="punctuation">]</span><span class="semi">;</span>
<span class="keyword">var</span> <span class="punctuation">{</span> a<span class="punctuation">,</span> <span class="mark">b<span class="punctuation"> = </span><span class="literal">2</span></span> <span class="punctuation">}</span><span class="punctuation"> = </span>obj<span class="semi">;</span>
<span class="keyword">var</span> <span class="punctuation">[</span> x<span class="punctuation">,</span> <span class="mark">y<span class="punctuation"> = </span><span class="literal">2</span></span> <span class="punctuation">]</span><span class="punctuation"> = </span>list<span class="semi">;</span>
</div>
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<div class="title"><b>ECMAScript 5</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code"><span class="keyword">var</span> obj<span class="punctuation"> = </span><span class="punctuation">{</span> a: <span class="literal">1</span> <span class="punctuation">}</span><span class="semi">;</span>
<span class="keyword">var</span> list<span class="punctuation"> = </span><span class="punctuation">[</span> <span class="literal">1</span> <span class="punctuation">]</span><span class="semi">;</span>
<span class="keyword">var</span> a<span class="punctuation"> = </span>obj<span class="punctuation">.</span>a<span class="semi">;</span>
<span class="keyword">var</span> <span class="mark">b<span class="punctuation"> = </span>obj<span class="punctuation">.</span>b <span class="punctuation">===</span> undefined ? <span class="literal">2</span> : obj<span class="punctuation">.</span>b</span><span class="semi">;</span>
<span class="keyword">var</span> x<span class="punctuation"> = </span>list<span class="punctuation">[</span><span class="literal">0</span><span class="punctuation">]</span><span class="semi">;</span>
<span class="keyword">var</span> <span class="mark">y<span class="punctuation"> = </span>list<span class="punctuation">[</span><span class="literal">1</span><span class="punctuation">]</span> <span class="punctuation">===</span> undefined ? <span class="literal">2</span> : list<span class="punctuation">[</span><span class="literal">1</span><span class="punctuation">]</span></span><span class="semi">;</span></div>
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</div>
<div id="ParameterContextMatching" class="showcase showcase_ParameterContextMatching"> <div class="title">Destructuring Assignment (解构赋值)</div>
<div class="subtitle">Parameter Context Matching (参数)</div>
<div class="desc">Intuitive and flexible destructuring of Arrays and Objects into individual parameters during function calls.</div>
<div class="js es6">
<div class="title"><b>ECMAScript 6</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code"><span class="keyword">function</span> f <span class="punctuation">(</span><span class="mark"><span class="punctuation">[</span> name<span class="punctuation">,</span> val <span class="punctuation">]</span></span><span class="punctuation">)</span> <span class="punctuation">{</span>
console<span class="punctuation">.</span>log<span class="punctuation">(</span>name<span class="punctuation">,</span> val<span class="punctuation">)</span><span class="semi">;</span>
<span class="punctuation">}</span>
<span class="keyword">function</span> g <span class="punctuation">(</span><span class="mark"><span class="punctuation">{</span> name: n<span class="punctuation">,</span> val: v <span class="punctuation">}</span></span><span class="punctuation">)</span> <span class="punctuation">{</span>
console<span class="punctuation">.</span>log<span class="punctuation">(</span>n<span class="punctuation">,</span> v<span class="punctuation">)</span><span class="semi">;</span>
<span class="punctuation">}</span>
<span class="keyword">function</span> h <span class="punctuation">(</span><span class="mark"><span class="punctuation">{</span> name<span class="punctuation">,</span> val <span class="punctuation">}</span></span><span class="punctuation">)</span> <span class="punctuation">{</span>
console<span class="punctuation">.</span>log<span class="punctuation">(</span>name<span class="punctuation">,</span> val<span class="punctuation">)</span><span class="semi">;</span>
<span class="punctuation">}</span>
f<span class="punctuation">(</span><span class="punctuation">[</span> <span class="literal">"bar"</span><span class="punctuation">,</span> <span class="literal">42</span> <span class="punctuation">]</span><span class="punctuation">)</span><span class="semi">;</span>
g<span class="punctuation">(</span><span class="punctuation">{</span> name: <span class="literal">"foo"</span><span class="punctuation">,</span> val: <span class="literal">7</span> <span class="punctuation">}</span><span class="punctuation">)</span><span class="semi">;</span>
h<span class="punctuation">(</span><span class="punctuation">{</span> name: <span class="literal">"bar"</span><span class="punctuation">,</span> val: <span class="literal">42</span> <span class="punctuation">}</span><span class="punctuation">)</span><span class="semi">;</span>
</div>
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<div class="title"><b>ECMAScript 5</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code"><span class="keyword">function</span> f <span class="punctuation">(</span><span class="mark">arg</span><span class="punctuation">)</span> <span class="punctuation">{</span>
<span class="mark"><span class="keyword">var</span> name<span class="punctuation"> = </span>arg<span class="punctuation">[</span><span class="literal">0</span><span class="punctuation">]</span></span><span class="semi">;</span>
<span class="mark"><span class="keyword">var</span> val <span class="punctuation"> = </span>arg<span class="punctuation">[</span><span class="literal">1</span><span class="punctuation">]</span></span><span class="semi">;</span>
console<span class="punctuation">.</span>log<span class="punctuation">(</span>name<span class="punctuation">,</span> val<span class="punctuation">)</span><span class="semi">;</span>
<span class="punctuation">}</span><span class="semi">;</span>
<span class="keyword">function</span> g <span class="punctuation">(</span><span class="mark">arg</span><span class="punctuation">)</span> <span class="punctuation">{</span>
<span class="mark"><span class="keyword">var</span> n<span class="punctuation"> = </span>arg<span class="punctuation">.</span>name</span><span class="semi">;</span>
<span class="mark"><span class="keyword">var</span> v<span class="punctuation"> = </span>arg<span class="punctuation">.</span>val</span><span class="semi">;</span>
console<span class="punctuation">.</span>log<span class="punctuation">(</span>n<span class="punctuation">,</span> v<span class="punctuation">)</span><span class="semi">;</span>
<span class="punctuation">}</span><span class="semi">;</span>
<span class="keyword">function</span> h <span class="punctuation">(</span><span class="mark">arg</span><span class="punctuation">)</span> <span class="punctuation">{</span>
<span class="mark"><span class="keyword">var</span> name<span class="punctuation"> = </span>arg<span class="punctuation">.</span>name</span><span class="semi">;</span>
<span class="mark"><span class="keyword">var</span> val <span class="punctuation"> = </span>arg<span class="punctuation">.</span>val</span><span class="semi">;</span>
console<span class="punctuation">.</span>log<span class="punctuation">(</span>name<span class="punctuation">,</span> val<span class="punctuation">)</span><span class="semi">;</span>
<span class="punctuation">}</span><span class="semi">;</span>
f<span class="punctuation">(</span><span class="punctuation">[</span> <span class="literal">"bar"</span><span class="punctuation">,</span> <span class="literal">42</span> <span class="punctuation">]</span><span class="punctuation">)</span><span class="semi">;</span>
g<span class="punctuation">(</span><span class="punctuation">{</span> name: <span class="literal">"foo"</span><span class="punctuation">,</span> val: <span class="literal">7</span> <span class="punctuation">}</span><span class="punctuation">)</span><span class="semi">;</span>
h<span class="punctuation">(</span><span class="punctuation">{</span> name: <span class="literal">"bar"</span><span class="punctuation">,</span> val: <span class="literal">42</span> <span class="punctuation">}</span><span class="punctuation">)</span><span class="semi">;</span></div>
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</div>
<div id="FailSoftDestructuring" class="showcase showcase_FailSoftDestructuring"> <div class="title">Destructuring Assignment (解构赋值)</div>
<div class="subtitle">Fail-Soft Destructuring (不会翻译)</div>
<div class="desc">Fail-soft destructuring, optionally with defaults.</div>
<div class="js es6">
<div class="title"><b>ECMAScript 6</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code"><span class="keyword">var</span> list<span class="punctuation"> = </span><span class="punctuation">[</span> <span class="literal">7</span><span class="punctuation">,</span> <span class="literal">42</span> <span class="punctuation">]</span><span class="semi">;</span>
<span class="keyword">var</span> <span class="punctuation">[</span> a<span class="punctuation"> = </span><span class="literal">1</span><span class="punctuation">,</span> b<span class="punctuation"> = </span><span class="literal">2</span><span class="punctuation">,</span> <span class="mark">c<span class="punctuation"> = </span><span class="literal">3</span></span><span class="punctuation">,</span> <span class="mark">d</span> <span class="punctuation">]</span><span class="punctuation"> = </span>list<span class="semi">;</span>
a <span class="punctuation">===</span> <span class="literal">7</span><span class="semi">;</span>
b <span class="punctuation">===</span> <span class="literal">42</span><span class="semi">;</span>
c <span class="punctuation">===</span> <span class="mark"><span class="literal">3</span></span><span class="semi">;</span>
d <span class="punctuation">===</span> <span class="mark">undefined</span><span class="semi">;</span>
</div>
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</div>
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<div class="title"><b>ECMAScript 5</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code"><span class="keyword">var</span> list<span class="punctuation"> = </span><span class="punctuation">[</span> <span class="literal">7</span><span class="punctuation">,</span> <span class="literal">42</span> <span class="punctuation">]</span><span class="semi">;</span>
<span class="keyword">var</span> a<span class="punctuation"> = </span>typeof list<span class="punctuation">[</span><span class="literal">0</span><span class="punctuation">]</span> !== <span class="literal">"undefined"</span> ? list<span class="punctuation">[</span><span class="literal">0</span><span class="punctuation">]</span> : <span class="literal">1</span><span class="semi">;</span>
<span class="keyword">var</span> b<span class="punctuation"> = </span>typeof list<span class="punctuation">[</span><span class="literal">1</span><span class="punctuation">]</span> !== <span class="literal">"undefined"</span> ? list<span class="punctuation">[</span><span class="literal">1</span><span class="punctuation">]</span> : <span class="literal">2</span><span class="semi">;</span>
<span class="keyword">var</span> c<span class="punctuation"> = </span>typeof list<span class="punctuation">[</span><span class="literal">2</span><span class="punctuation">]</span> !== <span class="literal">"undefined"</span> ? list<span class="punctuation">[</span><span class="literal">2</span><span class="punctuation">]</span> : <span class="mark"><span class="literal">3</span></span><span class="semi">;</span>
<span class="keyword">var</span> d<span class="punctuation"> = </span>typeof list<span class="punctuation">[</span><span class="literal">3</span><span class="punctuation">]</span> !== <span class="literal">"undefined"</span> ? list<span class="punctuation">[</span><span class="literal">3</span><span class="punctuation">]</span> : <span class="mark">undefined</span><span class="semi">;</span>
a <span class="punctuation">===</span> <span class="literal">7</span><span class="semi">;</span>
b <span class="punctuation">===</span> <span class="literal">42</span><span class="semi">;</span>
c <span class="punctuation">===</span> <span class="mark"><span class="literal">3</span></span><span class="semi">;</span>
d <span class="punctuation">===</span> <span class="mark">undefined</span><span class="semi">;</span></div>
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</div>
</div>
<div id="ValueExportImport" class="showcase showcase_ValueExportImport"> <div class="title">Modules (模块)</div>
<div class="subtitle">Value Export/Import (导入/导入)</div>
<div class="desc">Support for exporting/importing values from/to modules without global namespace pollution.</div>
<div class="js es6">
<div class="title"><b>ECMAScript 6</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code"><span class="comment">// lib/math<span class="punctuation">.</span>js</span>
<span class="mark"><span class="keyword">export</span></span> <span class="keyword">function</span> <span class="mark">sum</span> <span class="punctuation">(</span>x<span class="punctuation">,</span> y<span class="punctuation">)</span> <span class="punctuation">{</span> <span class="keyword">return</span> x <span class="punctuation">+</span> y <span class="punctuation">}</span><span class="semi">;</span>
<span class="mark"><span class="keyword">export</span></span> <span class="keyword">var</span> <span class="mark">pi</span><span class="punctuation"> = </span><span class="literal">3</span><span class="punctuation">.</span><span class="literal">141593</span><span class="semi">;</span>
<span class="comment">
// someApp<span class="punctuation">.</span>js</span>
<span class="mark"><span class="keyword">import</span> <span class="punctuation">*</span> as math</span> from <span class="literal">"lib/math"</span><span class="semi">;</span>
console<span class="punctuation">.</span>log<span class="punctuation">(</span><span class="literal">"2π<span class="punctuation"> = </span>"</span> <span class="punctuation">+</span> math<span class="punctuation">.</span>sum<span class="punctuation">(</span>math<span class="punctuation">.</span>pi<span class="punctuation">,</span> math<span class="punctuation">.</span>pi<span class="punctuation">)</span><span class="punctuation">)</span><span class="semi">;</span>
<span class="comment">
// otherApp<span class="punctuation">.</span>js</span>
<span class="mark"><span class="keyword">import</span> <span class="punctuation">{</span> sum<span class="punctuation">,</span> pi <span class="punctuation">}</span></span> from <span class="literal">"lib/math"</span><span class="semi">;</span>
console<span class="punctuation">.</span>log<span class="punctuation">(</span><span class="literal">"2π<span class="punctuation"> = </span>"</span> <span class="punctuation">+</span> sum<span class="punctuation">(</span>pi<span class="punctuation">,</span> pi<span class="punctuation">)</span><span class="punctuation">)</span><span class="semi">;</span>
</div>
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</div>
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<div class="title"><b>ECMAScript 5</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code"><span class="comment">// lib/math<span class="punctuation">.</span>js</span>
<span class="mark">LibMath<span class="punctuation"> = </span><span class="punctuation">{</span><span class="punctuation">}</span></span><span class="semi">;</span>
<span class="mark">LibMath<span class="punctuation">.</span>sum</span><span class="punctuation"> = </span><span class="keyword">function</span> <span class="punctuation">(</span>x<span class="punctuation">,</span> y<span class="punctuation">)</span> <span class="punctuation">{</span> <span class="keyword">return</span> x <span class="punctuation">+</span> y <span class="punctuation">}</span><span class="semi">;</span>
<span class="mark">LibMath<span class="punctuation">.</span>pi</span><span class="punctuation"> = </span><span class="literal">3</span><span class="punctuation">.</span><span class="literal">141593</span><span class="semi">;</span>
<span class="comment">
// someApp<span class="punctuation">.</span>js</span>
<span class="keyword">var</span> <span class="mark">math<span class="punctuation"> = </span>LibMath</span><span class="semi">;</span>
console<span class="punctuation">.</span>log<span class="punctuation">(</span><span class="literal">"2π<span class="punctuation"> = </span>"</span> <span class="punctuation">+</span> math<span class="punctuation">.</span>sum<span class="punctuation">(</span>math<span class="punctuation">.</span>pi<span class="punctuation">,</span> math<span class="punctuation">.</span>pi<span class="punctuation">)</span><span class="punctuation">)</span><span class="semi">;</span>
<span class="comment">
// otherApp<span class="punctuation">.</span>js</span>
<span class="keyword">var</span> <span class="mark">sum<span class="punctuation"> = </span>LibMath<span class="punctuation">.</span>sum</span><span class="punctuation">,</span> <span class="mark">pi<span class="punctuation"> = </span>LibMath<span class="punctuation">.</span>pi</span><span class="semi">;</span>
console<span class="punctuation">.</span>log<span class="punctuation">(</span><span class="literal">"2π<span class="punctuation"> = </span>"</span> <span class="punctuation">+</span> sum<span class="punctuation">(</span>pi<span class="punctuation">,</span> pi<span class="punctuation">)</span><span class="punctuation">)</span><span class="semi">;</span></div>
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</div>
</div>
<div id="DefaultWildcard" class="showcase showcase_DefaultWildcard"> <div class="title">Modules (模块)</div>
<div class="subtitle">Default & Wildcard (默认值 & 通配符)</div>
<div class="desc">Marking a value as the default exported value and mass-mixin of values.</div>
<div class="js es6">
<div class="title"><b>ECMAScript 6</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code"><span class="comment">// lib/mathplusplus<span class="punctuation">.</span>js</span>
<span class="mark"><span class="keyword">export</span> <span class="punctuation">*</span></span> from <span class="literal">"lib/math"</span><span class="semi">;</span>
<span class="keyword">export</span> <span class="keyword">var</span> e<span class="punctuation"> = </span><span class="literal">2</span><span class="punctuation">.</span><span class="literal">71828182846</span><span class="semi">;</span>
<span class="mark"><span class="keyword">export</span> default</span> <span class="punctuation">(</span>x<span class="punctuation">)</span> <span class="punctuation">=></span> Math<span class="punctuation">.</span>exp<span class="punctuation">(</span>x<span class="punctuation">)</span><span class="semi">;</span>
<span class="comment">
// someApp<span class="punctuation">.</span>js</span>
<span class="mark"><span class="keyword">import</span> exp<span class="punctuation">,</span> <span class="punctuation">{</span> pi<span class="punctuation">,</span> e <span class="punctuation">}</span></span> from <span class="literal">"lib/mathplusplus"</span><span class="semi">;</span>
console<span class="punctuation">.</span>log<span class="punctuation">(</span><span class="literal">"e^<span class="punctuation">{</span>π<span class="punctuation">}</span><span class="punctuation"> = </span>"</span> <span class="punctuation">+</span> exp<span class="punctuation">(</span>pi<span class="punctuation">)</span><span class="punctuation">)</span><span class="semi">;</span>
</div>
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</div>
<div class="arrow"><i class="fa fa-caret-up"></i><i class="fa fa-caret-down"></i></div><div class="js es5">
<div class="title"><b>ECMAScript 5</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code"><span class="comment">// lib/mathplusplus<span class="punctuation">.</span>js</span>
<span class="mark">LibMathPP<span class="punctuation"> = </span><span class="punctuation">{</span><span class="punctuation">}</span></span><span class="semi">;</span>
<span class="mark"><span class="keyword">for</span> <span class="punctuation">(</span>symbol <span class="keyword">in</span> LibMath<span class="punctuation">)</span></span>
<span class="mark"><span class="keyword">if</span> <span class="punctuation">(</span>LibMath<span class="punctuation">.</span>hasOwnProperty<span class="punctuation">(</span>symbol<span class="punctuation">)</span><span class="punctuation">)</span></span>
<span class="mark">LibMathPP<span class="punctuation">[</span>symbol<span class="punctuation">]</span><span class="punctuation"> = </span>LibMath<span class="punctuation">[</span>symbol<span class="punctuation">]</span></span><span class="semi">;</span>
<span class="mark">LibMathPP<span class="punctuation">.</span>e</span><span class="punctuation"> = </span><span class="literal">2</span><span class="punctuation">.</span><span class="literal">71828182846</span><span class="semi">;</span>
<span class="mark">LibMathPP<span class="punctuation">.</span>exp</span><span class="punctuation"> = </span><span class="keyword">function</span> <span class="punctuation">(</span>x<span class="punctuation">)</span> <span class="punctuation">{</span> <span class="keyword">return</span> Math<span class="punctuation">.</span>exp<span class="punctuation">(</span>x<span class="punctuation">)</span> <span class="punctuation">}</span><span class="semi">;</span>
<span class="comment">
// someApp<span class="punctuation">.</span>js</span>
<span class="keyword">var</span> <span class="mark">exp<span class="punctuation"> = </span>LibMathPP<span class="punctuation">.</span>exp</span><span class="punctuation">,</span> <span class="mark">pi<span class="punctuation"> = </span>LibMathPP<span class="punctuation">.</span>pi</span><span class="punctuation">,</span> <span class="mark">e<span class="punctuation"> = </span>LibMathPP<span class="punctuation">.</span>e</span><span class="semi">;</span>
console<span class="punctuation">.</span>log<span class="punctuation">(</span><span class="literal">"e^<span class="punctuation">{</span>π<span class="punctuation">}</span><span class="punctuation"> = </span>"</span> <span class="punctuation">+</span> exp<span class="punctuation">(</span>pi<span class="punctuation">)</span><span class="punctuation">)</span><span class="semi">;</span></div>
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</div>
</div>
<div id="ClassDefinition" class="showcase showcase_ClassDefinition"> <div class="title">Classes (类)</div>
<div class="subtitle">Class Definition (类定义)</div>
<div class="desc">More intuitive, OOP-style and boilerplate-free classes.</div>
<div class="js es6">
<div class="title"><b>ECMAScript 6</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code"><span class="mark"><span class="keyword">class</span></span> Shape <span class="punctuation">{</span>
<span class="mark">constructor</span> <span class="punctuation">(</span>id<span class="punctuation">,</span> x<span class="punctuation">,</span> y<span class="punctuation">)</span> <span class="punctuation">{</span>
<span class="keyword">this</span><span class="punctuation">.</span>id<span class="punctuation"> = </span>id<span class="semi">;</span>
<span class="keyword">this</span><span class="punctuation">.</span>move<span class="punctuation">(</span>x<span class="punctuation">,</span> y<span class="punctuation">)</span><span class="semi">;</span>
<span class="punctuation">}</span>
<span class="mark">move</span> <span class="punctuation">(</span>x<span class="punctuation">,</span> y<span class="punctuation">)</span> <span class="punctuation">{</span>
<span class="keyword">this</span><span class="punctuation">.</span>x<span class="punctuation"> = </span>x<span class="semi">;</span>
<span class="keyword">this</span><span class="punctuation">.</span>y<span class="punctuation"> = </span>y<span class="semi">;</span>
<span class="punctuation">}</span>
<span class="punctuation">}</span>
</div>
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</div>
<div class="arrow"><i class="fa fa-caret-up"></i><i class="fa fa-caret-down"></i></div><div class="js es5">
<div class="title"><b>ECMAScript 5</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code"><span class="keyword">var</span> Shape<span class="punctuation"> = </span><span class="mark"><span class="keyword">function</span></span> <span class="punctuation">(</span>id<span class="punctuation">,</span> x<span class="punctuation">,</span> y<span class="punctuation">)</span> <span class="punctuation">{</span>
<span class="keyword">this</span><span class="punctuation">.</span>id<span class="punctuation"> = </span>id<span class="semi">;</span>
<span class="keyword">this</span><span class="punctuation">.</span>move<span class="punctuation">(</span>x<span class="punctuation">,</span> y<span class="punctuation">)</span><span class="semi">;</span>
<span class="punctuation">}</span><span class="semi">;</span>
Shape<span class="punctuation">.</span><span class="mark">prototype<span class="punctuation">.</span>move</span><span class="punctuation"> = </span><span class="mark"><span class="keyword">function</span></span> <span class="punctuation">(</span>x<span class="punctuation">,</span> y<span class="punctuation">)</span> <span class="punctuation">{</span>
<span class="keyword">this</span><span class="punctuation">.</span>x<span class="punctuation"> = </span>x<span class="semi">;</span>
<span class="keyword">this</span><span class="punctuation">.</span>y<span class="punctuation"> = </span>y<span class="semi">;</span>
<span class="punctuation">}</span><span class="semi">;</span></div>
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</div>
</div>
<div id="ClassInheritance" class="showcase showcase_ClassInheritance"> <div class="title">Classes (类)</div>
<div class="subtitle">Class Inheritance (类继承)</div>
<div class="desc">More intuitive, OOP-style and boilerplate-free inheritance.</div>
<div class="js es6">
<div class="title"><b>ECMAScript 6</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code"><span class="mark"><span class="keyword">class</span></span> Rectangle <span class="mark"><span class="keyword">extends</span></span> Shape <span class="punctuation">{</span>
constructor <span class="punctuation">(</span>id<span class="punctuation">,</span> x<span class="punctuation">,</span> y<span class="punctuation">,</span> width<span class="punctuation">,</span> height<span class="punctuation">)</span> <span class="punctuation">{</span>
<span class="mark">super</span><span class="punctuation">(</span>id<span class="punctuation">,</span> x<span class="punctuation">,</span> y<span class="punctuation">)</span><span class="semi">;</span>
<span class="keyword">this</span><span class="punctuation">.</span>width <span class="punctuation"> = </span>width<span class="semi">;</span>
<span class="keyword">this</span><span class="punctuation">.</span>height<span class="punctuation"> = </span>height<span class="semi">;</span>
<span class="punctuation">}</span>
<span class="punctuation">}</span>
<span class="mark"><span class="keyword">class</span></span> Circle <span class="mark"><span class="keyword">extends</span></span> Shape <span class="punctuation">{</span>
constructor <span class="punctuation">(</span>id<span class="punctuation">,</span> x<span class="punctuation">,</span> y<span class="punctuation">,</span> radius<span class="punctuation">)</span> <span class="punctuation">{</span>
<span class="mark">super</span><span class="punctuation">(</span>id<span class="punctuation">,</span> x<span class="punctuation">,</span> y<span class="punctuation">)</span><span class="semi">;</span>
<span class="keyword">this</span><span class="punctuation">.</span>radius<span class="punctuation"> = </span>radius<span class="semi">;</span>
<span class="punctuation">}</span>
<span class="punctuation">}</span>
</div>
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</div>
<div class="arrow"><i class="fa fa-caret-up"></i><i class="fa fa-caret-down"></i></div><div class="js es5">
<div class="title"><b>ECMAScript 5</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code"><span class="keyword">var</span> Rectangle<span class="punctuation"> = </span><span class="keyword">function</span> <span class="punctuation">(</span>id<span class="punctuation">,</span> x<span class="punctuation">,</span> y<span class="punctuation">,</span> width<span class="punctuation">,</span> height<span class="punctuation">)</span> <span class="punctuation">{</span>
<span class="mark">Shape<span class="punctuation">.</span>call</span><span class="punctuation">(</span><span class="keyword">this</span><span class="punctuation">,</span> id<span class="punctuation">,</span> x<span class="punctuation">,</span> y<span class="punctuation">)</span><span class="semi">;</span>
<span class="keyword">this</span><span class="punctuation">.</span>width <span class="punctuation"> = </span>width<span class="semi">;</span>
<span class="keyword">this</span><span class="punctuation">.</span>height<span class="punctuation"> = </span>height<span class="semi">;</span>
<span class="punctuation">}</span><span class="semi">;</span>
<span class="mark">Rectangle<span class="punctuation">.</span>prototype<span class="punctuation"> = </span>Object<span class="punctuation">.</span>create<span class="punctuation">(</span>Shape<span class="punctuation">.</span>prototype<span class="punctuation">)</span></span><span class="semi">;</span>
<span class="mark">Rectangle<span class="punctuation">.</span>prototype<span class="punctuation">.</span>constructor<span class="punctuation"> = </span>Rectangle</span><span class="semi">;</span>
<span class="keyword">var</span> Circle<span class="punctuation"> = </span><span class="keyword">function</span> <span class="punctuation">(</span>id<span class="punctuation">,</span> x<span class="punctuation">,</span> y<span class="punctuation">,</span> radius<span class="punctuation">)</span> <span class="punctuation">{</span>
<span class="mark">Shape<span class="punctuation">.</span>call</span><span class="punctuation">(</span><span class="keyword">this</span><span class="punctuation">,</span> id<span class="punctuation">,</span> x<span class="punctuation">,</span> y<span class="punctuation">)</span><span class="semi">;</span>
<span class="keyword">this</span><span class="punctuation">.</span>radius<span class="punctuation"> = </span>radius<span class="semi">;</span>
<span class="punctuation">}</span><span class="semi">;</span>
<span class="mark">Circle<span class="punctuation">.</span>prototype<span class="punctuation"> = </span>Object<span class="punctuation">.</span>create<span class="punctuation">(</span>Shape<span class="punctuation">.</span>prototype<span class="punctuation">)</span></span><span class="semi">;</span>
<span class="mark">Circle<span class="punctuation">.</span>prototype<span class="punctuation">.</span>constructor<span class="punctuation"> = </span>Circle</span><span class="semi">;</span></div>
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</div>
</div>
<div id="ClassInheritanceFromExpressions" class="showcase showcase_ClassInheritanceFromExpressions"> <div class="title">Classes (类)</div>
<div class="subtitle">Class Inheritance, From Expressions (基类入口)</div>
<div class="desc">Support for mixin-style inheritance by extending from expressions yielding
function objects. [Notice: the generic <code>aggregation</code> function is usually provided
by a library like <a href="https://github.com/rse/aggregation">this one</a>, of course]</div>
<div class="js es6">
<div class="title"><b>ECMAScript 6</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code"><span class="keyword">var</span> <span class="mark">aggregation</span><span class="punctuation"> = </span><span class="punctuation">(</span>baseClass<span class="punctuation">,</span> <span class="punctuation">.</span><span class="punctuation">.</span><span class="punctuation">.</span>mixins<span class="punctuation">)</span> <span class="punctuation">=></span> <span class="punctuation">{</span>
<span class="keyword">let</span> base<span class="punctuation"> = </span><span class="keyword">class</span> _Combined <span class="keyword">extends</span> baseClass <span class="punctuation">{</span>
constructor <span class="punctuation">(</span><span class="punctuation">.</span><span class="punctuation">.</span><span class="punctuation">.</span>args<span class="punctuation">)</span> <span class="punctuation">{</span>
<span class="mark">super</span><span class="punctuation">(</span><span class="punctuation">.</span><span class="punctuation">.</span><span class="punctuation">.</span>args<span class="punctuation">)</span><span class="semi">;</span>
mixins<span class="punctuation">.</span>forEach<span class="punctuation">(</span><span class="punctuation">(</span>mixin<span class="punctuation">)</span> <span class="punctuation">=></span> <span class="punctuation">{</span>
mixin<span class="punctuation">.</span>prototype<span class="punctuation">.</span><span class="mark">initializer</span><span class="punctuation">.</span>call<span class="punctuation">(</span><span class="keyword">this</span><span class="punctuation">)</span><span class="semi">;</span>
<span class="punctuation">}</span><span class="punctuation">)</span><span class="semi">;</span>
<span class="punctuation">}</span>
<span class="punctuation">}</span><span class="semi">;</span>
<span class="keyword">let</span> copyProps<span class="punctuation"> = </span><span class="punctuation">(</span>target<span class="punctuation">,</span> source<span class="punctuation">)</span> <span class="punctuation">=></span> <span class="punctuation">{</span>
Object<span class="punctuation">.</span>getOwnPropertyNames<span class="punctuation">(</span>source<span class="punctuation">)</span>
<span class="punctuation">.</span>concat<span class="punctuation">(</span>Object<span class="punctuation">.</span>getOwnPropertySymbols<span class="punctuation">(</span>source<span class="punctuation">)</span><span class="punctuation">)</span>
<span class="punctuation">.</span>forEach<span class="punctuation">(</span><span class="punctuation">(</span>prop<span class="punctuation">)</span> <span class="punctuation">=></span> <span class="punctuation">{</span>
<span class="keyword">if</span> <span class="punctuation">(</span>prop<span class="punctuation">.</span>match<span class="punctuation">(</span>/^<span class="punctuation">(</span>?:constructor|prototype|arguments|caller|name|bind|call|apply|toString|length<span class="punctuation">)</span>$/<span class="punctuation">)</span><span class="punctuation">)</span>
<span class="keyword">return</span>
Object<span class="punctuation">.</span>defineProperty<span class="punctuation">(</span>target<span class="punctuation">,</span> prop<span class="punctuation">,</span> Object<span class="punctuation">.</span>getOwnPropertyDescriptor<span class="punctuation">(</span>source<span class="punctuation">,</span> prop<span class="punctuation">)</span><span class="punctuation">)</span>
<span class="punctuation">}</span><span class="punctuation">)</span>
<span class="punctuation">}</span>
mixins<span class="punctuation">.</span>forEach<span class="punctuation">(</span><span class="punctuation">(</span>mixin<span class="punctuation">)</span> <span class="punctuation">=></span> <span class="punctuation">{</span>
copyProps<span class="punctuation">(</span>base<span class="punctuation">.</span>prototype<span class="punctuation">,</span> mixin<span class="punctuation">.</span>prototype<span class="punctuation">)</span><span class="semi">;</span>
copyProps<span class="punctuation">(</span>base<span class="punctuation">,</span> mixin<span class="punctuation">)</span><span class="semi">;</span>
<span class="punctuation">}</span><span class="punctuation">)</span><span class="semi">;</span>
<span class="keyword">return</span> base<span class="semi">;</span>
<span class="punctuation">}</span><span class="semi">;</span>
<span class="keyword">class</span> <span class="mark">Colored</span> <span class="punctuation">{</span>
<span class="mark">initializer</span> <span class="punctuation">(</span><span class="punctuation">)</span> <span class="punctuation">{</span> <span class="keyword">this</span><span class="punctuation">.</span>_color<span class="punctuation"> = </span><span class="literal">"white"</span><span class="semi">;</span> <span class="punctuation">}</span>
get color <span class="punctuation">(</span><span class="punctuation">)</span> <span class="punctuation">{</span> <span class="keyword">return</span> <span class="keyword">this</span><span class="punctuation">.</span>_color<span class="semi">;</span> <span class="punctuation">}</span>
set color <span class="punctuation">(</span>v<span class="punctuation">)</span> <span class="punctuation">{</span> <span class="keyword">this</span><span class="punctuation">.</span>_color<span class="punctuation"> = </span>v<span class="semi">;</span> <span class="punctuation">}</span>
<span class="punctuation">}</span>
<span class="keyword">class</span> <span class="mark">ZCoord</span> <span class="punctuation">{</span>
<span class="mark">initializer</span> <span class="punctuation">(</span><span class="punctuation">)</span> <span class="punctuation">{</span> <span class="keyword">this</span><span class="punctuation">.</span>_z<span class="punctuation"> = </span><span class="literal">0</span><span class="semi">;</span> <span class="punctuation">}</span>
get z <span class="punctuation">(</span><span class="punctuation">)</span> <span class="punctuation">{</span> <span class="keyword">return</span> <span class="keyword">this</span><span class="punctuation">.</span>_z<span class="semi">;</span> <span class="punctuation">}</span>
set z <span class="punctuation">(</span>v<span class="punctuation">)</span> <span class="punctuation">{</span> <span class="keyword">this</span><span class="punctuation">.</span>_z<span class="punctuation"> = </span>v<span class="semi">;</span> <span class="punctuation">}</span>
<span class="punctuation">}</span>
<span class="keyword">class</span> <span class="mark">Shape</span> <span class="punctuation">{</span>
<span class="mark">constructor</span> <span class="punctuation">(</span>x<span class="punctuation">,</span> y<span class="punctuation">)</span> <span class="punctuation">{</span> <span class="keyword">this</span><span class="punctuation">.</span>_x<span class="punctuation"> = </span>x<span class="punctuation">;</span> <span class="keyword">this</span><span class="punctuation">.</span>_y<span class="punctuation"> = </span>y<span class="semi">;</span> <span class="punctuation">}</span>
get x <span class="punctuation">(</span><span class="punctuation">)</span> <span class="punctuation">{</span> <span class="keyword">return</span> <span class="keyword">this</span><span class="punctuation">.</span>_x<span class="semi">;</span> <span class="punctuation">}</span>
set x <span class="punctuation">(</span>v<span class="punctuation">)</span> <span class="punctuation">{</span> <span class="keyword">this</span><span class="punctuation">.</span>_x<span class="punctuation"> = </span>v<span class="semi">;</span> <span class="punctuation">}</span>
get y <span class="punctuation">(</span><span class="punctuation">)</span> <span class="punctuation">{</span> <span class="keyword">return</span> <span class="keyword">this</span><span class="punctuation">.</span>_y<span class="semi">;</span> <span class="punctuation">}</span>
set y <span class="punctuation">(</span>v<span class="punctuation">)</span> <span class="punctuation">{</span> <span class="keyword">this</span><span class="punctuation">.</span>_y<span class="punctuation"> = </span>v<span class="semi">;</span> <span class="punctuation">}</span>
<span class="punctuation">}</span>
<span class="keyword">class</span> Rectangle <span class="keyword">extends</span> <span class="mark">aggregation<span class="punctuation">(</span>Shape<span class="punctuation">,</span> Colored<span class="punctuation">,</span> ZCoord<span class="punctuation">)</span></span> <span class="punctuation">{</span><span class="punctuation">}</span>
<span class="keyword">var</span> rect<span class="punctuation"> = </span><span class="keyword">new</span> Rectangle<span class="punctuation">(</span><span class="literal">7</span><span class="punctuation">,</span> <span class="literal">42</span><span class="punctuation">)</span><span class="semi">;</span>
rect<span class="punctuation">.</span><span class="mark">z</span> <span class="punctuation"> = </span><span class="literal">1000</span><span class="semi">;</span>
rect<span class="punctuation">.</span><span class="mark">color</span><span class="punctuation"> = </span><span class="literal">"red"</span><span class="semi">;</span>
console<span class="punctuation">.</span>log<span class="punctuation">(</span>rect<span class="punctuation">.</span>x<span class="punctuation">,</span> rect<span class="punctuation">.</span>y<span class="punctuation">,</span> rect<span class="punctuation">.</span>z<span class="punctuation">,</span> rect<span class="punctuation">.</span>color<span class="punctuation">)</span><span class="semi">;</span>
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<div class="title"><b>ECMAScript 5</b> — syntactic sugar: <span class="style reduced">reduced</span> | <span class="style traditional">traditional</span></div>
<div class="code"><span class="keyword">var</span> <span class="mark">aggregation</span><span class="punctuation"> = </span><span class="keyword">function</span> <span class="punctuation">(</span>baseClass<span class="punctuation">,</span> mixins<span class="punctuation">)</span> <span class="punctuation">{</span>
<span class="keyword">var</span> base<span class="punctuation"> = </span><span class="keyword">function</span> <span class="punctuation">(</span><span class="punctuation">)</span> <span class="punctuation">{</span>
<span class="mark">baseClass<span class="punctuation">.</span>apply</span><span class="punctuation">(</span><span class="keyword">this</span><span class="punctuation">,</span> arguments<span class="punctuation">)</span><span class="semi">;</span>
mixins<span class="punctuation">.</span>forEach<span class="punctuation">(</span><span class="keyword">function</span> <span class="punctuation">(</span>mixin<span class="punctuation">)</span> <span class="punctuation">{</span>
mixin<span class="punctuation">.</span>prototype<span class="punctuation">.</span><span class="mark">initializer</span><span class="punctuation">.</span>call<span class="punctuation">(</span><span class="keyword">this</span><span class="punctuation">)</span><span class="semi">;</span>
<span class="punctuation">}</span><span class="punctuation">.</span>bind<span class="punctuation">(</span><span class="keyword">this</span><span class="punctuation">)</span><span class="punctuation">)</span><span class="semi">;</span>
<span class="punctuation">}</span><span class="semi">;</span>
base<span class="punctuation">.</span>prototype<span class="punctuation"> = </span>Object<span class="punctuation">.</span>create<span class="punctuation">(</span>baseClass<span class="punctuation">.</span>prototype<span class="punctuation">)</span><span class="semi">;</span>
base<span class="punctuation">.</span>prototype<span class="punctuation">.</span>constructor<span class="punctuation"> = </span>base<span class="semi">;</span>
<span class="keyword">var</span> copyProps<span class="punctuation"> = </span><span class="keyword">function</span> <span class="punctuation">(</span>target<span class="punctuation">,</span> source<span class="punctuation">)</span> <span class="punctuation">{</span>
Object<span class="punctuation">.</span>getOwnPropertyNames<span class="punctuation">(</span>source<span class="punctuation">)</span><span class="punctuation">.</span>forEach<span class="punctuation">(</span><span class="keyword">function</span> <span class="punctuation">(</span>prop<span class="punctuation">)</span> <span class="punctuation">{</span>
<span class="keyword">if</span> <span class="punctuation">(</span>prop<span class="punctuation">.</span>match<span class="punctuation">(</span>/^<span class="punctuation">(</span>?:constructor|prototype|arguments|caller|name|bind|call|apply|toString|length<span class="punctuation">)</span>$/<span class="punctuation">)</span><span class="punctuation">)</span>
<span class="keyword">return</span>
Object<span class="punctuation">.</span>defineProperty<span class="punctuation">(</span>target<span class="punctuation">,</span> prop<span class="punctuation">,</span> Object<span class="punctuation">.</span>getOwnPropertyDescriptor<span class="punctuation">(</span>source<span class="punctuation">,</span> prop<span class="punctuation">)</span><span class="punctuation">)</span>
<span class="punctuation">}</span><span class="punctuation">)</span>
<span class="punctuation">}</span>
mixins<span class="punctuation">.</span>forEach<span class="punctuation">(</span><span class="keyword">function</span> <span class="punctuation">(</span>mixin<span class="punctuation">)</span> <span class="punctuation">{</span>
copyProps<span class="punctuation">(</span>base<span class="punctuation">.</span>prototype<span class="punctuation">,</span> mixin<span class="punctuation">.</span>prototype<span class="punctuation">)</span><span class="semi">;</span>
copyProps<span class="punctuation">(</span>base<span class="punctuation">,</span> mixin<span class="punctuation">)</span><span class="semi">;</span>
<span class="punctuation">}</span><span class="punctuation">)</span><span class="semi">;</span>
<span class="keyword">return</span> base<span class="semi">;</span>
<span class="punctuation">}</span><span class="semi">;</span>
<span class="keyword">var</span> Colored<span class="punctuation"> = </span><span class="keyword">function</span> <span class="punctuation">(</span><span class="punctuation">)</span> <span class="punctuation">{</span><span class="punctuation">}</span><span class="semi">;</span>
Colored<span class="punctuation">.</span>prototype<span class="punctuation"> = </span><span class="punctuation">{</span>
<span class="mark">initializer</span>: <span class="keyword">function</span> <span class="punctuation">(</span><span class="punctuation">)</span> <span class="punctuation">{</span> <span class="keyword">this</span><span class="punctuation">.</span>_color<span class="punctuation"> = </span><span class="literal">"white"</span><span class="semi">;</span> <span class="punctuation">}</span><span class="punctuation">,</span>
getColor: <span class="keyword">function</span> <span class="punctuation">(</span><span class="punctuation">)</span> <span class="punctuation">{</span> <span class="keyword">return</span> <span class="keyword">this</span><span class="punctuation">.</span>_color<span class="semi">;</span> <span class="punctuation">}</span><span class="punctuation">,</span>
setColor: <span class="keyword">function</span> <span class="punctuation">(</span>v<span class="punctuation">)</span> <span class="punctuation">{</span> <span class="keyword">this</span><span class="punctuation">.</span>_color<span class="punctuation"> = </span>v<span class="semi">;</span> <span class="punctuation">}</span>
<span class="punctuation">}</span><span class="semi">;</span>
<span class="keyword">var</span> ZCoord<span class="punctuation"> = </span><span class="keyword">function</span> <span class="punctuation">(</span><span class="punctuation">)</span> <span class="punctuation">{</span><span class="punctuation">}</span><span class="semi">;</span>
ZCoord<span class="punctuation">.</span>prototype<span class="punctuation"> = </span><span class="punctuation">{</span>
<span class="mark">initializer</span>: <span class="keyword">function</span> <span class="punctuation">(</span><span class="punctuation">)</span> <span class="punctuation">{</span> <span class="keyword">this</span><span class="punctuation">.</span>_z<span class="punctuation"> = </span><span class="literal">0</span><span class="semi">;</span> <span class="punctuation">}</span><span class="punctuation">,</span>
getZ: <span class="keyword">function</span> <span class="punctuation">(</span><span class="punctuation">)</span> <span class="punctuation">{</span> <span class="keyword">return</span> <span class="keyword">this</span><span class="punctuation">.</span>_z<span class="semi">;</span> <span class="punctuation">}</span><span class="punctuation">,</span>
setZ: <span class="keyword">function</span> <span class="punctuation">(</span>v<span class="punctuation">)</span> <span class="punctuation">{</span> <span class="keyword">this</span><span class="punctuation">.</span>_z<span class="punctuation"> = </span>v<span class="semi">;</span> <span class="punctuation">}</span>
<span class="punctuation">}</span><span class="semi">;</span>
<span class="keyword">var</span> Shape<span class="punctuation"> = </span><span class="keyword">function</span> <span class="punctuation">(</span>x<span class="punctuation">,</span> y<span class="punctuation">)</span> <span class="punctuation">{</span>
<span class="keyword">this</span><span class="punctuation">.</span>_x<span class="punctuation"> = </span>x<span class="punctuation">;</span> <span class="keyword">this</span><span class="punctuation">.</span>_y<span class="punctuation"> = </span>y<span class="semi">;</span>
<span class="punctuation">}</span><span class="semi">;</span>
Shape<span class="punctuation">.</span>prototype<span class="punctuation"> = </span><span class="punctuation">{</span>
getX: <span class="keyword">function</span> <span class="punctuation">(</span><span class="punctuation">)</span> <span class="punctuation">{</span> <span class="keyword">return</span> <span class="keyword">this</span><span class="punctuation">.</span>_x<span class="semi">;</span> <span class="punctuation">}</span><span class="punctuation">,</span>
setX: <span class="keyword">function</span> <span class="punctuation">(</span>v<span class="punctuation">)</span> <span class="punctuation">{</span> <span class="keyword">this</span><span class="punctuation">.</span>_x<span class="punctuation"> = </span>v<span class="semi">;</span> <span class="punctuation">}</span><span class="punctuation">,</span>
getY: <span class="keyword">function</span> <span class="punctuation">(</span><span class="punctuation">)</span> <span class="punctuation">{</span> <span class="keyword">return</span> <span class="keyword">this</span><span class="punctuation">.</span>_y<span class="semi">;</span> <span class="punctuation">}</span><span class="punctuation">,</span>
setY: <span class="keyword">function</span> <span class="punctuation">(</span>v<span class="punctuation">)</span> <span class="punctuation">{</span> <span class="keyword">this</span><span class="punctuation">.</span>_y<span class="punctuation"> = </span>v<span class="semi">;</span> <span class="punctuation">}</span>
<span class="punctuation">}</span>
<span class="keyword">var</span> _Combined<span class="punctuation"> = </span><span class="mark">aggregation<span class="punctuation">(</span>Shape<span class="punctuation">,</span> <span class="punctuation">[</span> Colored<span class="punctuation">,</span> ZCoord <span class="punctuation">]</span><span class="punctuation">)</span></span><span class="semi">;</span>
<span class="keyword">var</span> Rectangle<span class="punctuation"> = </span><span class="keyword">function</span> <span class="punctuation">(</span>x<span class="punctuation">,</span> y<span class="punctuation">)</span> <span class="punctuation">{</span>
_Combined<span class="punctuation">.</span>call<span class="punctuation">(</span><span class="keyword">this</span><span class="punctuation">,</span> x<span class="punctuation">,</span> y<span class="punctuation">)</span><span class="semi">;</span>
<span class="punctuation">}</span><span class="semi">;</span>
Rectangle<span class="punctuation">.</span>prototype<span class="punctuation"> = </span>Object<span class="punctuation">.</span>create<span class="punctuation">(</span>_Combined<span class="punctuation">.</span>prototype<span class="punctuation">)</span><span class="semi">;</span>
Rectangle<span class="punctuation">.</span>prototype<span class="punctuation">.</span>constructor<span class="punctuation"> = </span>Rectangle<span class="semi">;</span>
<span class="keyword">var</span> rect<span class="punctuation"> = </span><span class="keyword">new</span> Rectangle<span class="punctuation">(</span><span class="literal">7</span><span class="punctuation">,</span> <span class="literal">42</span><span class="punctuation">)</span><span class="semi">;</span>
rect<span class="punctuation">.</span><span class="mark">setZ</span><span class="punctuation">(</span><span class="literal">1000</span><span class="punctuation">)</span><span class="semi">;</span>