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  19.     <span class="token function">render</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    20. 

  20.         <span class="token keyword">return</span> <span class="token operator">&lt;</span>img alt<span class="token operator">=</span><span class="token punctuation">{</span><span class="token keyword">this</span><span class="token punctuation">.</span>props<span class="token punctuation">.</span>caption<span class="token punctuation">}</span> src<span class="token operator">=</span><span class="token punctuation">{</span><span class="token keyword">this</span><span class="token punctuation">.</span>props<span class="token punctuation">.</span>src<span class="token punctuation">}</span> <span class="token operator">/</span><span class="token operator">&gt;</span>
    21. 

  21.     <span class="token punctuation">}</span>
    22. 

  22. <span class="token punctuation">}</span>
    23. 

  23. <span class="token comment">// The ES5 way</span>
    24. 

  24. <span class="token keyword">var</span> Photo <span class="token operator">=</span> React<span class="token punctuation">.</span><span class="token function">createClass</span><span class="token punctuation">(</span><span class="token punctuation">{</span>
    25. 

  25.     <span class="token function-variable function">handleDoubleTap</span><span class="token punctuation">:</span> <span class="token keyword">function</span><span class="token punctuation">(</span><span class="token parameter">e</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token operator">...</span> <span class="token punctuation">}</span>
    26. 

  26.     <span class="token function-variable function">render</span><span class="token punctuation">:</span> <span class="token keyword">function</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token operator">...</span> <span class="token punctuation">}</span>
    27. 

  27. <span class="token punctuation">}</span><span class="token punctuation">)</span>
    28. 

  28. <span class="token comment">//ThE ES6 way</span>
    29. 

  29. <span class="token keyword">class</span> <span class="token class-name">Photo</span> <span class="token keyword">extends</span> <span class="token class-name">React<span class="token punctuation">.</span>Component</span> <span class="token punctuation">{</span>
    30. 

  30.     <span class="token function">handleDoubleTap</span><span class="token punctuation">(</span><span class="token parameter">e</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token operator">...</span> <span class="token punctuation">}</span>
    31. 

  31.     <span class="token function">render</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token operator">...</span> <span class="token punctuation">}</span>
    32. 

  32. <span class="token punctuation">}</span>
    33. 

  33. </code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br></div></div><h2 id="生命周期方法"><a href="#生命周期方法" class="header-anchor">#</a> 生命周期方法</h2> <blockquote><p>所有的生命周期方法，但可以定义为使用新的类语法期望的。该课程 constructor 现在承担以前填写的角色 componentWillMount：</p></blockquote> <div class="language-javascript line-numbers-mode"><pre class="language-javascript"><code><span class="token comment">// es5</span>
    34. 

  34. <span class="token keyword">var</span> EmbedModal <span class="token operator">=</span> React<span class="token punctuation">.</span><span class="token function">createClass</span><span class="token punctuation">(</span><span class="token punctuation">{</span>
    35. 

  35.     <span class="token function-variable function">componentWillMount</span><span class="token punctuation">:</span> <span class="token keyword">function</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token operator">...</span> <span class="token punctuation">}</span>
    36. 

  36. <span class="token punctuation">}</span><span class="token punctuation">)</span>
    37. 

  37. <span class="token comment">// es6</span>
    38. 

  38. <span class="token keyword">class</span> <span class="token class-name">EmbedModal</span> <span class="token keyword">extends</span> <span class="token class-name">React<span class="token punctuation">.</span>createClass</span> <span class="token punctuation">(</span>
    39. 

  39.     <span class="token function">construtor</span><span class="token punctuation">(</span><span class="token parameter">props</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    40. 

  40.         <span class="token keyword">super</span><span class="token punctuation">(</span>props<span class="token punctuation">)</span><span class="token punctuation">;</span>
    41. 

  41.         <span class="token comment">// Operations usually carried out in componentWillMount go here</span>
    42. 

  42.     <span class="token punctuation">}</span>
    43. 

  43. <span class="token punctuation">)</span>
    44. 

  44. </code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br></div></div><h2 id="属性初始化"><a href="#属性初始化" class="header-anchor">#</a> 属性初始化</h2> <blockquote><p>ES7 属性初始化器在类的构造函数中运行，其中 this 指的是正在构建的类的实例，所以初始状态仍然可以依赖于 this.props。值得注意的是，我们不再需要根据吸气功能定义道具默认值和初始状态对象。</p></blockquote> <div class="language-javascript line-numbers-mode"><pre class="language-javascript"><code><span class="token comment">// es5</span>
    45. 

  45. <span class="token keyword">var</span> Video <span class="token operator">=</span> React<span class="token punctuation">.</span><span class="token function">createClass</span><span class="token punctuation">(</span><span class="token punctuation">{</span>
    46. 

  46.   <span class="token function-variable function">getDefaultProps</span><span class="token punctuation">:</span> <span class="token keyword">function</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    47. 

  47.     <span class="token keyword">return</span> <span class="token punctuation">{</span>
    48. 

  48.       autoPlay<span class="token punctuation">:</span> flase<span class="token punctuation">,</span>
    49. 

  49.       maxLoops<span class="token punctuation">:</span> <span class="token number">10</span><span class="token punctuation">,</span>
    50. 

  50.     <span class="token punctuation">}</span><span class="token punctuation">;</span>
    51. 

  51.   <span class="token punctuation">}</span><span class="token punctuation">,</span>
    52. 

  52.   <span class="token function-variable function">getInitalState</span><span class="token punctuation">:</span> <span class="token keyword">function</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    53. 

  53.     <span class="token keyword">return</span> <span class="token punctuation">{</span>
    54. 

  54.       loopsRemaining<span class="token punctuation">:</span> <span class="token keyword">this</span><span class="token punctuation">.</span>props<span class="token punctuation">.</span>maxloops<span class="token punctuation">,</span>
    55. 

  55.     <span class="token punctuation">}</span><span class="token punctuation">;</span>
    56. 

  56.   <span class="token punctuation">}</span><span class="token punctuation">,</span>
    57. 

  57.   propsTypes<span class="token punctuation">:</span> <span class="token punctuation">{</span>
    58. 

  58.     autoPlay<span class="token punctuation">:</span> React<span class="token punctuation">.</span>PropsTypes<span class="token punctuation">.</span>bool<span class="token punctuation">.</span>isRequired<span class="token punctuation">,</span>
    59. 

  59.     maxloops<span class="token punctuation">:</span> React<span class="token punctuation">.</span>PropsTypes<span class="token punctuation">.</span>number<span class="token punctuation">.</span>isRequired<span class="token punctuation">,</span>
    60. 

  60.     posterFrameSrc<span class="token punctuation">:</span> React<span class="token punctuation">.</span>PropsTypes<span class="token punctuation">.</span>string<span class="token punctuation">.</span>isRequired<span class="token punctuation">,</span>
    61. 

  61.     videoSrc<span class="token punctuation">:</span> React<span class="token punctuation">.</span>PropsTypes<span class="token punctuation">.</span>string<span class="token punctuation">.</span>isRequired<span class="token punctuation">,</span>
    62. 

  62.   <span class="token punctuation">}</span><span class="token punctuation">,</span>
    63. 

  63. <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    64. 

  64. <span class="token comment">// es6</span>
    65. 

  65. <span class="token keyword">class</span> <span class="token class-name">Video</span> <span class="token keyword">extends</span> <span class="token class-name">React<span class="token punctuation">.</span>Component</span> <span class="token punctuation">{</span>
    66. 

  66.   <span class="token keyword">static</span> defaultProps <span class="token operator">=</span> <span class="token punctuation">{</span>
    67. 

  67.     autoPlay<span class="token punctuation">:</span> <span class="token boolean">false</span><span class="token punctuation">,</span>
    68. 

  68.     maxloops<span class="token punctuation">:</span> <span class="token number">10</span><span class="token punctuation">,</span>
    69. 

  69.   <span class="token punctuation">}</span><span class="token punctuation">;</span>
    70. 

  70.   <span class="token keyword">static</span> propsTypes <span class="token operator">=</span> <span class="token punctuation">{</span>
    71. 

  71.     autoPlay<span class="token punctuation">:</span> React<span class="token punctuation">.</span>PropsTypes<span class="token punctuation">.</span>bool<span class="token punctuation">.</span>isRequired<span class="token punctuation">,</span>
    72. 

  72.     maxloops<span class="token punctuation">:</span> React<span class="token punctuation">.</span>propsTypes<span class="token punctuation">.</span>number<span class="token punctuation">.</span>isRequired<span class="token punctuation">,</span>
    73. 

  73.     posterFrameSrc<span class="token punctuation">:</span> React<span class="token punctuation">.</span>PropsTypes<span class="token punctuation">.</span>string<span class="token punctuation">.</span>isRequired<span class="token punctuation">,</span>
    74. 

  74.     videoSrc<span class="token punctuation">:</span> React<span class="token punctuation">.</span>PropsTypes<span class="token punctuation">.</span>string<span class="token punctuation">.</span>isRequired<span class="token punctuation">,</span>
    75. 

  75.   <span class="token punctuation">}</span><span class="token punctuation">;</span>
    76. 

  76.   state <span class="token operator">=</span> <span class="token punctuation">{</span>
    77. 

  77.     loopsRemaining<span class="token punctuation">:</span> <span class="token keyword">this</span><span class="token punctuation">.</span>props<span class="token punctuation">.</span>maxloops<span class="token punctuation">,</span>
    78. 

  78.   <span class="token punctuation">}</span><span class="token punctuation">;</span>
    79. 

  79. <span class="token punctuation">}</span>
    80. 

  80. </code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br><span class="line-number">26</span><br><span class="line-number">27</span><br><span class="line-number">28</span><br><span class="line-number">29</span><br><span class="line-number">30</span><br><span class="line-number">31</span><br><span class="line-number">32</span><br><span class="line-number">33</span><br><span class="line-number">34</span><br><span class="line-number">35</span><br><span class="line-number">36</span><br></div></div><h2 id="箭头函数说明"><a href="#箭头函数说明" class="header-anchor">#</a> 箭头函数说明</h2> <blockquote><p>该 React.createClass 方法用于对组件的实例方法执行一些额外的绑定工作，以确保其中的 this 关键字将引用该组件的实例。</p></blockquote> <div class="language-javascript line-numbers-mode"><pre class="language-javascript"><code><span class="token comment">// 自动绑定React.createClass</span>
    81. 

  81. <span class="token keyword">var</span> PostInfo <span class="token operator">=</span> React<span class="token punctuation">.</span><span class="token function">createClass</span><span class="token punctuation">(</span><span class="token punctuation">{</span>
    82. 

  82.   <span class="token function-variable function">handleOptionsButtonClick</span><span class="token punctuation">:</span> <span class="token keyword">function</span><span class="token punctuation">(</span><span class="token parameter">e</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    83. 

  83.     <span class="token comment">// 这里，'this' 是指组件实例。</span>
    84. 

  84.     <span class="token keyword">this</span><span class="token punctuation">.</span><span class="token function">setState</span><span class="token punctuation">(</span><span class="token punctuation">{</span> showOptionModal<span class="token punctuation">:</span> <span class="token boolean">true</span> <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    85. 

  85.   <span class="token punctuation">}</span><span class="token punctuation">,</span>
    86. 

  86. <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    87. 

  87. </code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br></div></div><blockquote><p>由于我们 React.createClass 在使用 ES6 +类语法定义组件时不涉及该方法，所以我们需要手动绑定实例方法，无论我们想要这种行为：</p></blockquote> <div class="language-javascript line-numbers-mode"><pre class="language-javascript"><code><span class="token comment">// 手动绑定，无论你是否需要</span>
    88. 

  88. <span class="token keyword">class</span> <span class="token class-name">PostInfo</span> <span class="token keyword">extends</span> <span class="token class-name">React<span class="token punctuation">.</span>Component</span> <span class="token punctuation">{</span>
    89. 

  89.   <span class="token function">construtor</span><span class="token punctuation">(</span><span class="token parameter">props</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    90. 

  90.     <span class="token keyword">super</span><span class="token punctuation">(</span>props<span class="token punctuation">)</span><span class="token punctuation">;</span>
    91. 

  91.     <span class="token comment">// 手动将此方法绑定到组件实例中…</span>
    92. 

  92.     <span class="token keyword">this</span><span class="token punctuation">.</span>handleOptionsButtonClick <span class="token operator">=</span> <span class="token keyword">this</span><span class="token punctuation">.</span><span class="token function">handleOptionsButtonClick</span><span class="token punctuation">.</span><span class="token function">bind</span><span class="token punctuation">(</span><span class="token keyword">this</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    93. 

  93.   <span class="token punctuation">}</span>
    94. 

  94.   <span class="token function">handleOptionsButtonClick</span><span class="token punctuation">(</span><span class="token parameter">e</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    95. 

  95.     <span class="token comment">// …为了确保'this'指的是组件实例。</span>
    96. 

  96.     <span class="token keyword">this</span><span class="token punctuation">.</span><span class="token function">setState</span><span class="token punctuation">(</span><span class="token punctuation">{</span> showOptionsModal<span class="token punctuation">:</span> <span class="token boolean">true</span> <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    97. 

  97.   <span class="token punctuation">}</span>
    98. 

  98. <span class="token punctuation">}</span>
    99. 

  99. </code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br></div></div><blockquote><p>幸运的是，通过组合两个 ES6 +功能 - 箭头函数和属性初始值设置 - 选择加入到组件实例的绑定变得轻而易举：</p></blockquote> <div class="language-javascript line-numbers-mode"><pre class="language-javascript"><code><span class="token keyword">class</span> <span class="token class-name">PostInfo</span> <span class="token keyword">extends</span> <span class="token class-name">React<span class="token punctuation">.</span>Component</span> <span class="token punctuation">{</span>
    100. 

  100.   <span class="token function-variable function">handleOptionsButtonClick</span> <span class="token operator">=</span> <span class="token punctuation">(</span><span class="token parameter">e</span><span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token punctuation">{</span>
    101. 

  101.     <span class="token keyword">this</span><span class="token punctuation">.</span><span class="token function">setState</span><span class="token punctuation">(</span><span class="token punctuation">{</span> showOptionsModal<span class="token punctuation">:</span> <span class="token boolean">true</span> <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    102. 

  102.   <span class="token punctuation">}</span><span class="token punctuation">;</span>
    103. 

  103. <span class="token punctuation">}</span>
    104. 

  104. </code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br></div></div><blockquote><p>ES6 箭头函数的主体具有与它们周围 this 的代码相同的词汇，这使得我们获得了期望的结果，因为 ES7 属性初始化器的作用域的方式。在罩下看，看看为什么这个工作。</p></blockquote> <h2 id="动态属性名称和模板字符串"><a href="#动态属性名称和模板字符串" class="header-anchor">#</a> 动态属性名称和模板字符串</h2> <blockquote><p>其中的增强对象文本包括分配给派生属性名称的能力。我们原本可以做这样的事情来设定一个状态：</p></blockquote> <div class="language-javascript line-numbers-mode"><pre class="language-javascript"><code><span class="token keyword">var</span> From <span class="token operator">=</span> React<span class="token punctuation">.</span><span class="token function">createClass</span><span class="token punctuation">(</span><span class="token punctuation">{</span>
    105. 

  105.   <span class="token function-variable function">onChange</span><span class="token punctuation">:</span> <span class="token keyword">function</span><span class="token punctuation">(</span><span class="token parameter">inputName<span class="token punctuation">,</span> e</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    106. 

  106.     <span class="token keyword">var</span> stateToSet <span class="token operator">=</span> <span class="token punctuation">{</span><span class="token punctuation">}</span><span class="token punctuation">;</span>
    107. 

  107.     stateToSet<span class="token punctuation">[</span>inputName <span class="token operator">+</span> <span class="token string">'Value'</span><span class="token punctuation">]</span> <span class="token operator">=</span> e<span class="token punctuation">.</span>targe<span class="token punctuation">.</span>value<span class="token punctuation">;</span>
    108. 

  108.     <span class="token keyword">this</span><span class="token punctuation">.</span><span class="token function">setState</span><span class="token punctuation">(</span>stateToset<span class="token punctuation">)</span><span class="token punctuation">;</span>
    109. 

  109.   <span class="token punctuation">}</span><span class="token punctuation">,</span>
    110. 

  110. <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    111. 

  111. <span class="token comment">// 现在，我们有能力构建在运行时由JavaScript表达式决定其属性名称的对象。在这里，我们使用模板字符串来确定要设置的属性：</span>
    112. 

  112. <span class="token keyword">class</span> <span class="token class-name">From</span> <span class="token keyword">extends</span> <span class="token class-name">React<span class="token punctuation">.</span>Component</span> <span class="token punctuation">{</span>
    113. 

  113.   <span class="token function">onChange</span><span class="token punctuation">(</span><span class="token parameter">inpuntName<span class="token punctuation">,</span> e</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    114. 

  114.     <span class="token keyword">this</span><span class="token punctuation">.</span><span class="token function">setState</span><span class="token punctuation">(</span><span class="token punctuation">{</span>
    115. 

  115.       <span class="token punctuation">[</span><span class="token template-string"><span class="token template-punctuation string">`</span><span class="token string">$(inputName)value</span><span class="token template-punctuation string">`</span></span><span class="token punctuation">]</span><span class="token punctuation">:</span> e<span class="token punctuation">.</span>targe<span class="token punctuation">.</span>value<span class="token punctuation">,</span>
    116. 

  116.     <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    117. 

  117.   <span class="token punctuation">}</span>
    118. 

  118. <span class="token punctuation">}</span>
    119. 

  119. </code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br></div></div><h2 id="解构和传播属性"><a href="#解构和传播属性" class="header-anchor">#</a> 解构和传播属性</h2> <blockquote><p>通常在组成组件时，我们可能希望将大部分父组件的道具传递给子组件，但并不是全部。将 ES6 + 解构与 JSX 传播属性相结合，无需仪式即可实现：</p></blockquote> <div class="language-javascript line-numbers-mode"><pre class="language-javascript"><code><span class="token keyword">class</span> <span class="token class-name">AutoloadingPostsGrid</span> <span class="token keyword">extends</span> <span class="token class-name">React<span class="token punctuation">.</span>Component</span> <span class="token punctuation">{</span>
    120. 

  120.     <span class="token function">render</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    121. 

  121.         <span class="token keyword">const</span> <span class="token punctuation">{</span>
    122. 

  122.             className<span class="token punctuation">,</span>
    123. 

  123.             <span class="token operator">...</span>others <span class="token comment">// 包含所有特性this.props除了类名</span>
    124. 

  124.         <span class="token punctuation">}</span> <span class="token operator">=</span> <span class="token keyword">this</span><span class="token punctuation">.</span>props<span class="token punctuation">;</span>
    125. 

  125.         <span class="token keyword">return</span> <span class="token punctuation">(</span>
    126. 

  126.             <span class="token operator">&lt;</span>div className<span class="token operator">=</span><span class="token punctuation">{</span>className<span class="token punctuation">}</span><span class="token operator">&gt;</span>
    127. 

  127.                 <span class="token operator">&lt;</span>PostsGrid <span class="token punctuation">{</span><span class="token operator">...</span>others<span class="token punctuation">}</span> <span class="token operator">/</span><span class="token operator">&gt;</span>
    128. 

  128.                 <span class="token operator">&lt;</span>button onClick<span class="token operator">=</span><span class="token punctuation">{</span><span class="token keyword">this</span><span class="token punctuation">.</span>handleLoadMoreClick<span class="token punctuation">}</span><span class="token operator">&gt;</span>Load more<span class="token operator">&lt;</span><span class="token operator">/</span>button<span class="token operator">&gt;</span>
    129. 

  129.             <span class="token operator">&lt;</span><span class="token operator">/</span>div<span class="token operator">&gt;</span>
    130. 

  130.         <span class="token punctuation">)</span><span class="token punctuation">;</span>
    131. 

  131.     <span class="token punctuation">}</span>
    132. 

  132. <span class="token punctuation">}</span>
    133. 

  133. <span class="token comment">// 我们可以将JSX传播属性与常规属性结合起来，利用简单的优先级规则来实现覆盖和默认值。该元素将获得className“覆盖”，即使存在一个className财产this.props：</span>
    134. 

  134. <span class="token operator">&lt;</span>div <span class="token punctuation">{</span><span class="token operator">...</span>this<span class="token punctuation">.</span>props<span class="token punctuation">}</span> className<span class="token operator">=</span><span class="token string">&quot;override&quot;</span><span class="token operator">&gt;</span>
    135. 

  135.     <span class="token operator">...</span>
    136. 

  136. <span class="token operator">&lt;</span><span class="token operator">/</span>div<span class="token operator">&gt;</span>
    137. 

  137. <span class="token comment">// This element will regularly have the “base” unless there exists a property in to override it:</span>
    138. 

  138. <span class="token operator">&lt;</span>div className<span class="token operator">=</span><span class="token string">&quot;base&quot;</span> <span class="token punctuation">{</span><span class="token operator">...</span>this<span class="token punctuation">.</span>props<span class="token punctuation">}</span><span class="token operator">&gt;</span>
    139. 

  139.   <span class="token operator">...</span>
    140. 

  140. <span class="token operator">&lt;</span><span class="token operator">/</span>div<span class="token operator">&gt;</span>
    141. 

  141. </code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br></div></div><h2 id="模块"><a href="#模块" class="header-anchor">#</a> 模块</h2> <div class="language-javascript line-numbers-mode"><pre class="language-javascript"><code><span class="token comment">// 引用</span>
    142. 

  142. <span class="token comment">// es5</span>
    143. 

  143. <span class="token keyword">var</span> React <span class="token operator">=</span> <span class="token function">require</span><span class="token punctuation">(</span><span class="token string">&quot;react&quot;</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    144. 

  144. <span class="token keyword">var</span> <span class="token punctuation">{</span>
    145. 

  145.     Component<span class="token punctuation">,</span>
    146. 

  146.     PropsTypes
    147. 

  147. <span class="token punctuation">}</span> <span class="token operator">=</span> React<span class="token punctuation">;</span> <span class="token comment">//引用react抽象组件</span>
    148. 

  148. 

  149. <span class="token keyword">var</span> ReactNative <span class="token operator">=</span> <span class="token function">require</span><span class="token punctuation">(</span><span class="token string">&quot;react-native&quot;</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    150. 

  150. <span class="token keyword">var</span> <span class="token punctuation">{</span>
    151. 

  151.     Image<span class="token punctuation">,</span>
    152. 

  152.     Text<span class="token punctuation">,</span>
    153. 

  153. <span class="token punctuation">}</span> <span class="token operator">=</span> ReactNative<span class="token punctuation">;</span> <span class="token comment">// 引用具体的React Native组件</span>
    154. 

  154. 

  155. <span class="token comment">// es6 import写法更为标准</span>
    156. 

  156. <span class="token keyword">import</span> React<span class="token punctuation">,</span> <span class="token punctuation">{</span>
    157. 

  157.     Component<span class="token punctuation">,</span>
    158. 

  158.     PropsTypes<span class="token punctuation">,</span>
    159. 

  159. <span class="token punctuation">}</span> <span class="token keyword">from</span> <span class="token string">'react'</span><span class="token punctuation">;</span>
    160. 

  160. <span class="token keyword">import</span> <span class="token punctuation">{</span>
    161. 

  161.     imange，
    162. 

  162.     Text<span class="token punctuation">,</span>
    163. 

  163. <span class="token punctuation">}</span> <span class="token keyword">from</span> <span class="token string">'react-native'</span>
    164. 

  164. </code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br></div></div><h2 id="导出单个类"><a href="#导出单个类" class="header-anchor">#</a> 导出单个类</h2> <blockquote><p>在 ES5 里，要导出一个类给别的模块用，一般通过 module.exports 来导出</p></blockquote> <div class="language-javascript line-numbers-mode"><pre class="language-javascript"><code><span class="token comment">// es5</span>
    165. 

  165. <span class="token keyword">var</span> MyComponent <span class="token operator">=</span> React<span class="token punctuation">.</span><span class="token function">createClass</span><span class="token punctuation">(</span><span class="token punctuation">{</span>
    166. 

  166.   <span class="token comment">// 函数</span>
    167. 

  167. <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    168. 

  168. <span class="token comment">// es6</span>
    169. 

  169. <span class="token keyword">export</span> <span class="token keyword">default</span> <span class="token keyword">class</span> <span class="token class-name">MyComponent</span> <span class="token keyword">extends</span> <span class="token class-name">Component</span> <span class="token punctuation">{</span>
    170. 

  170.   <span class="token comment">// 函数</span>
    171. 

  171. <span class="token punctuation">}</span>
    172. 

  172. <span class="token comment">// 引用 class</span>
    173. 

  173. <span class="token comment">// es5</span>
    174. 

  174. <span class="token keyword">var</span> MyComponent <span class="token operator">=</span> <span class="token function">require</span><span class="token punctuation">(</span><span class="token string">'./MyComponent'</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    175. 

  175. <span class="token comment">// es6</span>
    176. 

  176. <span class="token keyword">import</span> MyComponent <span class="token keyword">from</span> <span class="token string">'./MyComponent'</span><span class="token punctuation">;</span>
    177. 

  177. </code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br></div></div><h2 id="定义组件"><a href="#定义组件" class="header-anchor">#</a> 定义组件</h2> <blockquote><p>es5 在 ES5 里，通常通过 React.createClass 来定义一个组件类，像这样：</p></blockquote> <div class="language-javascript line-numbers-mode"><pre class="language-javascript"><code><span class="token keyword">var</span> Photo <span class="token operator">=</span> React<span class="token punctuation">.</span><span class="token function">createClass</span><span class="token punctuation">(</span><span class="token punctuation">{</span>
    178. 

  178.   <span class="token function-variable function">render</span><span class="token punctuation">:</span> <span class="token keyword">function</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    179. 

  179.     <span class="token keyword">return</span> <span class="token operator">&lt;</span>Image source<span class="token operator">=</span><span class="token punctuation">{</span><span class="token keyword">this</span><span class="token punctuation">.</span>props<span class="token punctuation">.</span>source<span class="token punctuation">}</span> <span class="token operator">/</span><span class="token operator">&gt;</span><span class="token punctuation">;</span>
    180. 

  180.   <span class="token punctuation">}</span><span class="token punctuation">,</span>
    181. 

  181. <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    182. 

  182. </code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br></div></div><blockquote><p>在 ES6 里，我们通过定义一个继承自 React.Component 的 class 来定义一个组件类，像这样：</p></blockquote> <div class="language-javascript line-numbers-mode"><pre class="language-javascript"><code><span class="token keyword">class</span> <span class="token class-name">Photo</span> <span class="token keyword">extends</span> <span class="token class-name">React<span class="token punctuation">.</span>Component</span> <span class="token punctuation">{</span>
    183. 

  183.   <span class="token function">render</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    184. 

  184.     <span class="token keyword">return</span> <span class="token operator">&lt;</span>Image source<span class="token operator">=</span><span class="token punctuation">{</span><span class="token keyword">this</span><span class="token punctuation">.</span>props<span class="token punctuation">.</span>source<span class="token punctuation">}</span> <span class="token operator">/</span><span class="token operator">&gt;</span><span class="token punctuation">;</span>
    185. 

  185.   <span class="token punctuation">}</span>
    186. 

  186. <span class="token punctuation">}</span>
    187. 

  187. </code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br></div></div><h2 id="给组件定义方法"><a href="#给组件定义方法" class="header-anchor">#</a> 给组件定义方法</h2> <blockquote><p>给组件定义方法不再用 名字: function()的写法，而是直接用名字()，在方法的最后也不能有逗号了。</p></blockquote> <div class="language-javascript line-numbers-mode"><pre class="language-javascript"><code><span class="token comment">// es5</span>
    188. 

  188. <span class="token keyword">var</span> Photo <span class="token operator">=</span> React<span class="token punctuation">.</span><span class="token function">createClass</span><span class="token punctuation">(</span><span class="token punctuation">{</span>
    189. 

  189.     <span class="token function-variable function">componentWillMount</span><span class="token punctuation">:</span> <span class="token keyword">function</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    190. 

  190.         <span class="token comment">// 函数</span>
    191. 

  191.     <span class="token punctuation">}</span><span class="token punctuation">,</span>
    192. 

  192.     <span class="token function-variable function">render</span><span class="token punctuation">:</span> <span class="token keyword">function</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    193. 

  193.         <span class="token keyword">return</span> <span class="token punctuation">(</span>
    194. 

  194.             <span class="token operator">&lt;</span>Image source<span class="token operator">=</span><span class="token punctuation">{</span><span class="token keyword">this</span><span class="token punctuation">.</span>props<span class="token punctuation">.</span>source<span class="token punctuation">}</span> <span class="token operator">/</span><span class="token operator">&gt;</span>
    195. 

  195.         <span class="token punctuation">)</span><span class="token punctuation">;</span>
    196. 

  196.     <span class="token punctuation">}</span><span class="token punctuation">,</span>
    197. 

  197. <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    198. 

  198. 

  199. <span class="token comment">// es6</span>
    200. 

  200. <span class="token keyword">class</span> <span class="token class-name">Photo</span> <span class="token keyword">extends</span> <span class="token class-name">React<span class="token punctuation">.</span>Component</span> <span class="token punctuation">{</span>
    201. 

  201.     <span class="token function">componentWillMount</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    202. 

  202.         <span class="token comment">// 函数</span>
    203. 

  203.     <span class="token punctuation">}</span><span class="token punctuation">,</span>
    204. 

  204.     <span class="token function">render</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    205. 

  205.         <span class="token keyword">return</span> <span class="token punctuation">(</span>
    206. 

  206.             <span class="token operator">&lt;</span>Image source<span class="token operator">=</span><span class="token punctuation">{</span><span class="token keyword">this</span><span class="token punctuation">.</span>props<span class="token punctuation">.</span>source<span class="token punctuation">}</span> <span class="token operator">/</span><span class="token operator">&gt;</span>
    207. 

  207.         <span class="token punctuation">)</span><span class="token punctuation">;</span>
    208. 

  208.     <span class="token punctuation">}</span>
    209. 

  209. <span class="token punctuation">}</span>
    210. 

  210. </code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br></div></div><h2 id="定义组件的属性类型和默认属性"><a href="#定义组件的属性类型和默认属性" class="header-anchor">#</a> 定义组件的属性类型和默认属性</h2> <blockquote><p>在 ES5 里，属性类型和默认属性分别通过 propTypes 成员和 getDefaultProps 方法来实现</p></blockquote> <div class="language-javascript line-numbers-mode"><pre class="language-javascript"><code><span class="token comment">// es5</span>
    211. 

  211. <span class="token keyword">var</span> video <span class="token operator">=</span> React<span class="token punctuation">.</span><span class="token function">createClass</span><span class="token punctuation">(</span><span class="token punctuation">{</span>
    212. 

  212.     <span class="token function-variable function">getDefaultProps</span><span class="token punctuation">:</span> <span class="token keyword">function</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    213. 

  213.         <span class="token keyword">return</span> <span class="token punctuation">{</span>
    214. 

  214.             autoPlay<span class="token punctuation">:</span> <span class="token boolean">false</span><span class="token punctuation">,</span>
    215. 

  215.             maxloops<span class="token punctuation">:</span> <span class="token number">10</span><span class="token punctuation">,</span>
    216. 

  216.         <span class="token punctuation">}</span><span class="token punctuation">;</span>
    217. 

  217.     <span class="token punctuation">}</span><span class="token punctuation">,</span>
    218. 

  218.     PropsTypes<span class="token punctuation">:</span> <span class="token punctuation">{</span>
    219. 

  219.         autoPlay<span class="token punctuation">:</span> React<span class="token punctuation">.</span>PropsTypes<span class="token punctuation">.</span>bool<span class="token punctuation">.</span>isRequired<span class="token punctuation">,</span>
    220. 

  220.         maxloops<span class="token punctuation">:</span> React<span class="token punctuation">.</span>PropsTypes<span class="token punctuation">.</span>number<span class="token punctuation">.</span>isRequired<span class="token punctuation">,</span>
    221. 

  221.         posterFrameSrc<span class="token punctuation">:</span> React<span class="token punctuation">.</span>PropsTypes<span class="token punctuation">.</span>string<span class="token punctuation">.</span>isRequired<span class="token punctuation">,</span>
    222. 

  222.         videoSrc<span class="token punctuation">:</span> React<span class="token punctuation">.</span>PropsTypes<span class="token punctuation">.</span>string<span class="token punctuation">.</span>isRequired<span class="token punctuation">,</span>
    223. 

  223.     <span class="token punctuation">}</span><span class="token punctuation">,</span>
    224. 

  224.     <span class="token function-variable function">render</span><span class="token punctuation">:</span> <span class="token keyword">function</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    225. 

  225.         <span class="token function-variable function">return</span><span class="token punctuation">:</span> <span class="token keyword">function</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    226. 

  226.             <span class="token operator">&lt;</span>View <span class="token operator">/</span><span class="token operator">&gt;</span>
    227. 

  227.         <span class="token punctuation">}</span><span class="token punctuation">;</span>
    228. 

  228.     <span class="token punctuation">}</span>
    229. 

  229. <span class="token punctuation">}</span><span class="token punctuation">)</span>
    230. 

  230. </code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br></div></div><blockquote><p>在 ES6 里，可以统一使用 static 成员来实现</p></blockquote> <div class="language-javascript line-numbers-mode"><pre class="language-javascript"><code><span class="token comment">//es6</span>
    231. 

  231. <span class="token keyword">class</span> <span class="token class-name">Video</span> <span class="token keyword">extends</span> <span class="token class-name">React<span class="token punctuation">.</span>Component</span> <span class="token punctuation">{</span>
    232. 

  232.   <span class="token keyword">static</span> defaultProps <span class="token operator">=</span> <span class="token punctuation">{</span>
    233. 

  233.     autoPlay<span class="token punctuation">:</span> flase<span class="token punctuation">,</span>
    234. 

  234.     maxloops<span class="token punctuation">:</span> <span class="token number">10</span><span class="token punctuation">,</span>
    235. 

  235.   <span class="token punctuation">}</span><span class="token punctuation">;</span> <span class="token comment">// 注意这里有分号</span>
    236. 

  236.   <span class="token keyword">static</span> propsTypes <span class="token operator">=</span> <span class="token punctuation">{</span>
    237. 

  237.     autoPlay<span class="token punctuation">:</span> React<span class="token punctuation">.</span>PropsTypes<span class="token punctuation">.</span>bool<span class="token punctuation">.</span>isRequired<span class="token punctuation">,</span>
    238. 

  238.     maxloops<span class="token punctuation">:</span> React<span class="token punctuation">.</span>PropsTypes<span class="token punctuation">.</span>number<span class="token punctuation">.</span>isRequired<span class="token punctuation">,</span>
    239. 

  239.     posterFrameSrc<span class="token punctuation">:</span> React<span class="token punctuation">.</span>PropsTypes<span class="token punctuation">.</span>string<span class="token punctuation">.</span>isRequired<span class="token punctuation">,</span>
    240. 

  240.     videoSrc<span class="token punctuation">:</span> React<span class="token punctuation">.</span>PropsTypes<span class="token punctuation">.</span>string<span class="token punctuation">.</span>isRequired<span class="token punctuation">,</span>
    241. 

  241.   <span class="token punctuation">}</span><span class="token punctuation">;</span> <span class="token comment">// 注意这里有分号</span>
    242. 

  242.   <span class="token function">render</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    243. 

  243.     <span class="token keyword">return</span> <span class="token operator">&lt;</span>view <span class="token operator">/</span><span class="token operator">&gt;</span><span class="token punctuation">;</span>
    244. 

  244.   <span class="token punctuation">}</span>
    245. 

  245. <span class="token punctuation">}</span>
    246. 

  246. </code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br></div></div><blockquote><p>也有人这么写，虽然不推荐，但读到代码的时候你应当能明白它的意思：</p></blockquote> <div class="language-javascript line-numbers-mode"><pre class="language-javascript"><code><span class="token comment">//es6</span>
    247. 

  247. <span class="token keyword">class</span> <span class="token class-name">Videlo</span> <span class="token keyword">extends</span> <span class="token class-name">React<span class="token punctuation">.</span>Component</span> <span class="token punctuation">{</span>
    248. 

  248.   <span class="token function">render</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    249. 

  249.     <span class="token keyword">return</span> <span class="token operator">&lt;</span>Video <span class="token operator">/</span><span class="token operator">&gt;</span><span class="token punctuation">;</span>
    250. 

  250.   <span class="token punctuation">}</span>
    251. 

  251. <span class="token punctuation">}</span>
    252. 

  252. Video<span class="token punctuation">.</span>defauleftProps <span class="token operator">=</span> <span class="token punctuation">{</span>
    253. 

  253.   autoPlay<span class="token punctuation">:</span> <span class="token boolean">false</span><span class="token punctuation">,</span>
    254. 

  254.   maxloops<span class="token punctuation">:</span> <span class="token number">10</span><span class="token punctuation">,</span>
    255. 

  255. <span class="token punctuation">}</span><span class="token punctuation">;</span>
    256. 

  256. Video<span class="token punctuation">.</span>propsTypes <span class="token operator">=</span> <span class="token punctuation">{</span>
    257. 

  257.   autoPlay<span class="token punctuation">:</span> React<span class="token punctuation">.</span>PropsTypes<span class="token punctuation">.</span>bool<span class="token punctuation">.</span>isRequired<span class="token punctuation">,</span>
    258. 

  258.   maxloops<span class="token punctuation">:</span> React<span class="token punctuation">.</span>PropsTypes<span class="token punctuation">.</span>number<span class="token punctuation">.</span>isRequired<span class="token punctuation">,</span>
    259. 

  259.   posterFrameSrc<span class="token punctuation">:</span> React<span class="token punctuation">.</span>PropsTypes<span class="token punctuation">.</span>string<span class="token punctuation">.</span>isRequired<span class="token punctuation">,</span>
    260. 

  260.   videoSrc<span class="token punctuation">:</span> React<span class="token punctuation">.</span>PropsTypes<span class="token punctuation">.</span>string<span class="token punctuation">.</span>isRequired<span class="token punctuation">,</span>
    261. 

  261. <span class="token punctuation">}</span><span class="token punctuation">;</span>
    262. 

  262. <span class="token comment">// 注意: 对React开发者而言，static成员在IE10及之前版本不能被继承，而在IE11和其它浏览器上可以，这有时候会带来一些问题。React Native开发者可以不用担心这个问题。</span>
    263. 

  263. </code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br></div></div><h2 id="初始化-state"><a href="#初始化-state" class="header-anchor">#</a> 初始化 STATE</h2> <div class="language-javascript line-numbers-mode"><pre class="language-javascript"><code><span class="token comment">// es5</span>
    264. 

  264. <span class="token keyword">var</span> video <span class="token operator">=</span> React<span class="token punctuation">.</span><span class="token function">createClass</span><span class="token punctuation">(</span><span class="token punctuation">{</span>
    265. 

  265.   <span class="token function-variable function">getInitalState</span><span class="token punctuation">:</span> <span class="token keyword">function</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    266. 

  266.     <span class="token keyword">return</span> <span class="token punctuation">{</span>
    267. 

  267.       loopsRemaining<span class="token punctuation">:</span> <span class="token keyword">this</span><span class="token punctuation">.</span>props<span class="token punctuation">.</span>maxloops<span class="token punctuation">,</span>
    268. 

  268.     <span class="token punctuation">}</span><span class="token punctuation">;</span>
    269. 

  269.   <span class="token punctuation">}</span><span class="token punctuation">,</span>
    270. 

  270. <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    271. 

  271. <span class="token comment">// ES6下，有两种写法：</span>
    272. 

  272. <span class="token keyword">class</span> <span class="token class-name">Video</span> <span class="token keyword">extends</span> <span class="token class-name">React<span class="token punctuation">.</span>Component</span> <span class="token punctuation">{</span>
    273. 

  273.   state <span class="token operator">=</span> <span class="token punctuation">{</span>
    274. 

  274.     loopsRemaining<span class="token punctuation">:</span> <span class="token keyword">this</span><span class="token punctuation">.</span>props<span class="token punctuation">.</span>maxloops<span class="token punctuation">,</span>
    275. 

  275.   <span class="token punctuation">}</span><span class="token punctuation">;</span>
    276. 

  276. <span class="token punctuation">}</span>
    277. 

  277. <span class="token comment">// 不过我们推荐更易理解的在构造函数中初始化（这样你还可以根据需要做一些计算）：</span>
    278. 

  278. <span class="token comment">// es6</span>
    279. 

  279. <span class="token keyword">class</span> <span class="token class-name">Video</span> <span class="token keyword">extends</span> <span class="token class-name">React<span class="token punctuation">.</span>Component</span> <span class="token punctuation">{</span>
    280. 

  280.   <span class="token function">construtor</span><span class="token punctuation">(</span><span class="token parameter">props</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    281. 

  281.     <span class="token keyword">super</span><span class="token punctuation">(</span>props<span class="token punctuation">)</span><span class="token punctuation">;</span>
    282. 

  282.     <span class="token keyword">this</span><span class="token punctuation">.</span>state <span class="token operator">=</span> <span class="token punctuation">{</span>
    283. 

  283.       loopsRemaining<span class="token punctuation">:</span> <span class="token keyword">this</span><span class="token punctuation">.</span>props<span class="token punctuation">.</span>maxloops<span class="token punctuation">,</span>
    284. 

  284.     <span class="token punctuation">}</span><span class="token punctuation">;</span>
    285. 

  285.   <span class="token punctuation">}</span>
    286. 

  286. <span class="token punctuation">}</span>
    287. 

  287. </code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br></div></div><h2 id="把方法作为回调提供"><a href="#把方法作为回调提供" class="header-anchor">#</a> 把方法作为回调提供</h2> <blockquote><p>很多习惯于 ES6 的用户反而不理解在 ES5 下可以这么做：</p></blockquote> <div class="language-javascript line-numbers-mode"><pre class="language-javascript"><code><span class="token keyword">var</span> PostInfo <span class="token operator">=</span> React<span class="token punctuation">.</span><span class="token function">createClass</span><span class="token punctuation">(</span><span class="token punctuation">{</span>
    288. 

  288.   <span class="token function-variable function">handleOptionsButtonClick</span><span class="token punctuation">:</span> <span class="token keyword">function</span><span class="token punctuation">(</span><span class="token parameter">e</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    289. 

  289.     <span class="token comment">// Here,'this' refers to the component instance</span>
    290. 

  290.     <span class="token keyword">this</span><span class="token punctuation">.</span><span class="token function">setState</span><span class="token punctuation">(</span><span class="token punctuation">{</span> showOptionModel<span class="token punctuation">:</span> <span class="token boolean">true</span> <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    291. 

  291.   <span class="token punctuation">}</span><span class="token punctuation">,</span>
    292. 

  292.   <span class="token function-variable function">render</span><span class="token punctuation">:</span> <span class="token keyword">function</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    293. 

  293.     <span class="token keyword">return</span> <span class="token punctuation">(</span>
    294. 

  294.       <span class="token operator">&lt;</span>TouchableHighlight onPress<span class="token operator">=</span><span class="token punctuation">{</span><span class="token keyword">this</span><span class="token punctuation">.</span>handleOptionsButtonClick<span class="token punctuation">}</span><span class="token operator">&gt;</span>
    295. 

  295.         <span class="token operator">&lt;</span>Text<span class="token operator">&gt;</span><span class="token punctuation">{</span><span class="token keyword">this</span><span class="token punctuation">.</span>props<span class="token punctuation">.</span>label<span class="token punctuation">}</span><span class="token operator">&lt;</span><span class="token operator">/</span>Text<span class="token operator">&gt;</span>
    296. 

  296.       <span class="token operator">&lt;</span><span class="token operator">/</span>TouchableHighlight<span class="token operator">&gt;</span>
    297. 

  297.     <span class="token punctuation">)</span><span class="token punctuation">;</span>
    298. 

  298.   <span class="token punctuation">}</span><span class="token punctuation">,</span>
    299. 

  299. <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    300. 

  300. </code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br></div></div><blockquote><p>在 ES5 下，React.createClass 会把所有的方法都 bind 一遍，这样可以提交到任意的地方作为回调函数，而 this 不会变化。但官方现在逐步认为这反而是不标准、不易理解的。</p></blockquote> <p>在 ES6 下，你需要通过 bind 来绑定 this 引用，或者使用箭头函数（它会绑定当前 scope 的 this 引用）来调用</p> <div class="language-javascript line-numbers-mode"><pre class="language-javascript"><code><span class="token comment">// es6</span>
    301. 

  301. <span class="token keyword">class</span> <span class="token class-name">PostInfo</span> <span class="token keyword">extends</span> <span class="token class-name">React<span class="token punctuation">.</span>Component</span>
    302. 

  302. <span class="token punctuation">{</span>
    303. 

  303.     <span class="token function">handleOptionsButtonClick</span><span class="token punctuation">(</span><span class="token parameter">e</span><span class="token punctuation">)</span><span class="token punctuation">{</span>
    304. 

  304.         <span class="token keyword">this</span><span class="token punctuation">.</span><span class="token function">setState</span><span class="token punctuation">(</span><span class="token punctuation">{</span>showOptionsModal<span class="token punctuation">:</span> <span class="token boolean">true</span><span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    305. 

  305.     <span class="token punctuation">}</span>
    306. 

  306.     <span class="token function">render</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    307. 

  307.         <span class="token keyword">return</span> <span class="token punctuation">(</span>
    308. 

  308.             <span class="token operator">&lt;</span>TouchableHighlight
    309. 

  309.                 onpress<span class="token operator">=</span><span class="token punctuation">{</span><span class="token keyword">this</span><span class="token punctuation">.</span><span class="token function">handleOptionsButtonClick</span><span class="token punctuation">.</span><span class="token function">bind</span><span class="token punctuation">(</span><span class="token keyword">this</span><span class="token punctuation">)</span><span class="token punctuation">}</span>
    310. 

  310.                 onpress<span class="token operator">=</span><span class="token punctuation">{</span><span class="token parameter">e</span><span class="token operator">=&gt;</span><span class="token keyword">this</span><span class="token punctuation">.</span><span class="token function">handleOptionsButtonClick</span><span class="token punctuation">(</span>e<span class="token punctuation">)</span><span class="token punctuation">}</span>
    311. 

  311.                 <span class="token operator">&gt;</span>
    312. 

  312.                 <span class="token operator">&lt;</span>Text<span class="token operator">&gt;</span><span class="token punctuation">{</span><span class="token keyword">this</span><span class="token punctuation">.</span>props<span class="token punctuation">.</span>label<span class="token punctuation">}</span><span class="token operator">&lt;</span><span class="token operator">/</span>Text<span class="token operator">&gt;</span>
    313. 

  313.             <span class="token operator">&lt;</span><span class="token operator">/</span>TouchableHighlight<span class="token operator">&gt;</span>
    314. 

  314.         <span class="token punctuation">)</span>
    315. 

  315.     <span class="token punctuation">}</span><span class="token punctuation">,</span>
    316. 

  316. <span class="token punctuation">}</span>
    317. 

  317. </code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br></div></div><h2 id="箭头函数"><a href="#箭头函数" class="header-anchor">#</a> 箭头函数</h2> <blockquote><p>箭头函数实际上是在这里定义了一个临时的函数，箭头函数的箭头=&gt;之前是一个空括号、单个的参数名、或用括号括起的多个参数名，而箭头之后可以是一个表达式（作为函数的返回值），或者是用花括号括起的函数体（需要自行通过 return 来返回值，否则返回的是 undefined）。</p></blockquote> <div class="language-javascript line-numbers-mode"><pre class="language-javascript"><code><span class="token comment">// 箭头函数实例</span>
    318. 

  318. <span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">=&gt;</span><span class="token number">1</span>
    319. 

  319. <span class="token parameter">v</span><span class="token operator">=&gt;</span>v<span class="token operator">+</span><span class="token number">1</span>
    320. 

  320. <span class="token punctuation">(</span><span class="token parameter">a<span class="token punctuation">,</span>b</span><span class="token punctuation">)</span><span class="token operator">=&gt;</span>a<span class="token operator">+</span><span class="token function">b</span>
    321. 

  321. <span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">=&gt;</span><span class="token punctuation">{</span>
    322. 

  322.     <span class="token function">alert</span><span class="token punctuation">(</span><span class="token string">'foo'</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    323. 

  323. <span class="token punctuation">}</span>
    324. 

  324. <span class="token parameter">e</span><span class="token operator">=&gt;</span><span class="token punctuation">{</span>
    325. 

  325.     <span class="token keyword">if</span> <span class="token punctuation">(</span>e <span class="token operator">==</span> <span class="token number">0</span><span class="token punctuation">)</span><span class="token punctuation">{</span>
    326. 

  326.         <span class="token keyword">return</span> <span class="token number">0</span><span class="token punctuation">;</span>
    327. 

  327.     <span class="token punctuation">}</span>
    328. 

  328.     <span class="token keyword">return</span> <span class="token number">1000</span><span class="token operator">/</span>e<span class="token punctuation">;</span>
    329. 

  329. <span class="token punctuation">}</span>
    330. 

  330. </code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br></div></div><blockquote><p>需要注意的是，不论是 bind 还是箭头函数，每次被执行都返回的是一个新的函数引用，因此如果你还需要函数的引用去做一些别的事情（譬如卸载监听器），那么你必须自己保存这个引用</p></blockquote> <div class="language-javascript line-numbers-mode"><pre class="language-javascript"><code><span class="token comment">// 错误的做法</span>
    331. 

  331. <span class="token keyword">class</span> <span class="token class-name">PaussMenu</span> <span class="token keyword">extends</span> <span class="token class-name">React<span class="token punctuation">.</span>Component</span> <span class="token punctuation">{</span>
    332. 

  332.   <span class="token function">componentWillMount</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    333. 

  333.     AppStateIOS<span class="token punctuation">.</span><span class="token function">addEventListener</span><span class="token punctuation">(</span><span class="token string">'change'</span><span class="token punctuation">,</span> <span class="token keyword">this</span><span class="token punctuation">.</span><span class="token function">onAppPaused</span><span class="token punctuation">.</span><span class="token function">bind</span><span class="token punctuation">(</span><span class="token keyword">this</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    334. 

  334.   <span class="token punctuation">}</span>
    335. 

  335.   <span class="token function">componentDidUnmount</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    336. 

  336.     AppStateIOS<span class="token punctuation">.</span><span class="token function">removeEventListener</span><span class="token punctuation">(</span><span class="token string">'change'</span><span class="token punctuation">,</span> <span class="token keyword">this</span><span class="token punctuation">.</span>onAppPaused<span class="token punctuation">.</span><span class="token function">buid</span><span class="token punctuation">(</span><span class="token keyword">this</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    337. 

  337.   <span class="token punctuation">}</span>
    338. 

  338.   <span class="token function">onAppPaused</span><span class="token punctuation">(</span><span class="token parameter">event</span><span class="token punctuation">)</span> <span class="token punctuation">{</span><span class="token punctuation">}</span>
    339. 

  339. <span class="token punctuation">}</span>
    340. 

  340. 

  341. <span class="token comment">// 正确的做法</span>
    342. 

  342. <span class="token keyword">class</span> <span class="token class-name">PaussMenu</span> <span class="token keyword">extends</span> <span class="token class-name">React<span class="token punctuation">.</span>Component</span> <span class="token punctuation">{</span>
    343. 

  343.   <span class="token function">construtor</span><span class="token punctuation">(</span><span class="token parameter">props</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    344. 

  344.     <span class="token keyword">super</span><span class="token punctuation">(</span>props<span class="token punctuation">)</span><span class="token punctuation">;</span>
    345. 

  345.     <span class="token keyword">this</span><span class="token punctuation">.</span>_OnAppPaused <span class="token operator">=</span> <span class="token keyword">this</span><span class="token punctuation">.</span><span class="token function">onAppPaused</span><span class="token punctuation">.</span><span class="token function">bind</span><span class="token punctuation">(</span><span class="token keyword">this</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    346. 

  346.   <span class="token punctuation">}</span>
    347. 

  347.   <span class="token function">componentWillMount</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    348. 

  348.     AppStateIOS<span class="token punctuation">.</span><span class="token function">addEventListener</span><span class="token punctuation">(</span><span class="token string">'change'</span><span class="token punctuation">,</span> <span class="token keyword">this</span><span class="token punctuation">.</span>_OnAppPaused<span class="token punctuation">)</span><span class="token punctuation">;</span>
    349. 

  349.   <span class="token punctuation">}</span>
    350. 

  350.   <span class="token function">componentDidUnmount</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    351. 

  351.     AppStateIOS<span class="token punctuation">.</span><span class="token function">removeEventListener</span><span class="token punctuation">(</span><span class="token string">'change'</span><span class="token punctuation">,</span> this_onAppPaused<span class="token punctuation">)</span><span class="token punctuation">;</span>
    352. 

  352.   <span class="token punctuation">}</span>
    353. 

  353.   <span class="token function">onAppPaused</span><span class="token punctuation">(</span><span class="token parameter">event</span><span class="token punctuation">)</span> <span class="token punctuation">{</span><span class="token punctuation">}</span>
    354. 

  354. <span class="token punctuation">}</span>
    355. 

  355. <span class="token comment">// 从这个帖子[这个帖子](http://www.tuicool.com/articles/Rj6RFnm)中我们还学习到一种新的做法：</span>
    356. 

  356. <span class="token comment">// 正确的做法</span>
    357. 

  357. <span class="token keyword">class</span> <span class="token class-name">PaussMenu</span> <span class="token keyword">extends</span> <span class="token class-name">React<span class="token punctuation">.</span>createClass</span> <span class="token punctuation">{</span>
    358. 

  358.   <span class="token function">componentWillMount</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    359. 

  359.     AppStateIOS<span class="token punctuation">.</span><span class="token function">addEventListener</span><span class="token punctuation">(</span><span class="token string">'change'</span><span class="token punctuation">,</span> <span class="token keyword">this</span><span class="token punctuation">.</span>onAppPaused<span class="token punctuation">)</span><span class="token punctuation">;</span>
    360. 

  360.   <span class="token punctuation">}</span>
    361. 

  361.   <span class="token function">componentDidUnmount</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    362. 

  362.     AppStateIOS<span class="token punctuation">.</span><span class="token function">removeEventListener</span><span class="token punctuation">(</span><span class="token string">'change'</span><span class="token punctuation">,</span> <span class="token keyword">this</span><span class="token punctuation">.</span>onAppPaused<span class="token punctuation">)</span><span class="token punctuation">;</span>
    363. 

  363.   <span class="token punctuation">}</span>
    364. 

  364.   <span class="token function-variable function">onAppPaused</span> <span class="token operator">=</span> <span class="token punctuation">(</span><span class="token parameter">event</span><span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token punctuation">{</span>
    365. 

  365.     <span class="token comment">// 把方法直接作为一个arrow function的属性来定义，初始化的时候就绑定好了this的指针</span>
    366. 

  366.   <span class="token punctuation">}</span><span class="token punctuation">;</span>
    367. 

  367. <span class="token punctuation">}</span>
    368. 

  368. </code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br><span class="line-number">26</span><br><span class="line-number">27</span><br><span class="line-number">28</span><br><span class="line-number">29</span><br><span class="line-number">30</span><br><span class="line-number">31</span><br><span class="line-number">32</span><br><span class="line-number">33</span><br><span class="line-number">34</span><br><span class="line-number">35</span><br><span class="line-number">36</span><br><span class="line-number">37</span><br><span class="line-number">38</span><br></div></div><h2 id="mixins"><a href="#mixins" class="header-anchor">#</a> Mixins</h2> <blockquote><p>在 ES5 下，我们经常使用 minxin 来为我们的类添加一些新的方法，譬如 PureRenderMinxin</p></blockquote> <div class="language-javascript line-numbers-mode"><pre class="language-javascript"><code><span class="token keyword">var</span> PurRenderMixin <span class="token operator">=</span> <span class="token function">require</span><span class="token punctuation">(</span><span class="token string">'react-addins-pure-render-minxin'</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    369. 

  369. React<span class="token punctuation">.</span><span class="token function">createClass</span><span class="token punctuation">(</span><span class="token punctuation">{</span>
    370. 

  370.   mixin<span class="token punctuation">:</span> <span class="token punctuation">[</span>PurRenderMixin<span class="token punctuation">]</span><span class="token punctuation">,</span>
    371. 

  371. 

  372.   <span class="token function-variable function">render</span><span class="token punctuation">:</span> <span class="token keyword">function</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    373. 

  373.     <span class="token keyword">return</span> <span class="token operator">&lt;</span>div className<span class="token operator">=</span><span class="token punctuation">{</span><span class="token keyword">this</span><span class="token punctuation">.</span>props<span class="token punctuation">.</span>className<span class="token punctuation">}</span><span class="token operator">&gt;</span>foo<span class="token operator">&lt;</span><span class="token operator">/</span>div<span class="token operator">&gt;</span><span class="token punctuation">;</span>
    374. 

  374.   <span class="token punctuation">}</span><span class="token punctuation">,</span>
    375. 

  375. <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    376. 

  376. </code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br></div></div><blockquote><p>然而现在官方已经不再打算在 ES6 里继续推行 Mixin，他们说：Mixins Are Dead. Long Live Composition。<br>
    377. 

  377. 尽管如果要继续使用 mixin，还是有一些第三方的方案可以用，譬如这个方案<br>
    378. 

  378. 不过官方推荐，对于库编写者而言，应当尽快放弃 Mixin 的编写方式，文中提到 Sebastian Markbåge 的一段代码推荐了一种新的编码方式：</p></blockquote> <div class="language-javascript line-numbers-mode"><pre class="language-javascript"><code><span class="token comment">//Enhance.js</span>
    379. 

  379. <span class="token keyword">import</span> <span class="token punctuation">{</span> Component <span class="token punctuation">}</span> <span class="token keyword">from</span> <span class="token string">'React'</span>
    380. 

  380. 

  381. <span class="token keyword">extends</span> <span class="token class-name">var</span> <span class="token function-variable function">Enhance</span> <span class="token operator">=</span> <span class="token parameter">ComposedComponent</span> <span class="token operator">=&gt;</span> <span class="token keyword">class</span> <span class="token class-name">extends</span> Component <span class="token punctuation">{</span>
    382. 

  382.     <span class="token function">construtor</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    383. 

  383.         <span class="token keyword">this</span><span class="token punctuation">.</span>state <span class="token operator">=</span> <span class="token punctuation">{</span>dtaa<span class="token punctuation">:</span><span class="token keyword">null</span><span class="token punctuation">}</span>
    384. 

  384.     <span class="token punctuation">}</span>
    385. 

  385.     <span class="token function">componentDidUnmount</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    386. 

  386.         <span class="token keyword">this</span><span class="token punctuation">.</span><span class="token function">setState</span><span class="token punctuation">(</span><span class="token punctuation">{</span> data<span class="token punctuation">:</span> <span class="token string">'Hello'</span> <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    387. 

  387.     <span class="token punctuation">}</span>
    388. 

  388.     <span class="token function">render</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    389. 

  389.         renturn <span class="token operator">&lt;</span>ComposedComponent <span class="token punctuation">{</span><span class="token operator">...</span>this<span class="token punctuation">.</span>props<span class="token punctuation">}</span> data<span class="token operator">=</span><span class="token punctuation">{</span><span class="token keyword">this</span><span class="token punctuation">.</span>state<span class="token punctuation">.</span>data<span class="token punctuation">}</span> <span class="token operator">/</span><span class="token operator">&gt;</span>
    390. 

  390.     <span class="token punctuation">}</span>
    391. 

  391. <span class="token punctuation">}</span>
    392. 

  392. 

  393. <span class="token comment">// HigherOrderComponent.js</span>
    394. 

  394. <span class="token keyword">import</span> <span class="token punctuation">{</span> Enhance <span class="token punctuation">}</span> <span class="token keyword">from</span> <span class="token string">&quot;./Enhance&quot;</span><span class="token punctuation">;</span>
    395. 

  395. 

  396. <span class="token keyword">class</span> <span class="token class-name">MyComponent</span> <span class="token punctuation">{</span>
    397. 

  397.     <span class="token function">render</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    398. 

  398.         <span class="token keyword">if</span> <span class="token punctuation">(</span><span class="token operator">!</span><span class="token keyword">this</span><span class="token punctuation">.</span>data<span class="token punctuation">)</span> <span class="token keyword">return</span> <span class="token operator">&lt;</span>div<span class="token operator">&gt;</span>Waiting<span class="token operator">...</span><span class="token operator">&lt;</span><span class="token operator">/</span>div<span class="token operator">&gt;</span><span class="token punctuation">;</span>
    399. 

  399.         <span class="token keyword">return</span> <span class="token operator">&lt;</span>div<span class="token operator">&gt;</span><span class="token punctuation">{</span><span class="token keyword">this</span><span class="token punctuation">.</span>data<span class="token punctuation">}</span><span class="token operator">&lt;</span><span class="token operator">/</span>div<span class="token operator">&gt;</span><span class="token punctuation">;</span>
    400. 

  400.     <span class="token punctuation">}</span>
    401. 

  401. <span class="token punctuation">}</span>
    402. 

  402. 

  403. <span class="token keyword">export</span> defaule <span class="token function">Enhance</span><span class="token punctuation">(</span>MyComponent<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">// Enhance component</span>
    404. 

  404. <span class="token comment">//用一个“增强函数”，来某个类增加一些方法，并且返回一个新类，这无疑能实现mixin所实现的大部分需求。</span>
    405. 

  405. </code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br><span class="line-number">26</span><br><span class="line-number">27</span><br></div></div><h2 id="es6-带来的其它好处"><a href="#es6-带来的其它好处" class="header-anchor">#</a> ES6+带来的其它好处</h2> <h3 id="解构-属性延展"><a href="#解构-属性延展" class="header-anchor">#</a> 解构&amp;属性延展</h3> <blockquote><p>结合使用 ES6+的解构和属性延展，我们给孩子传递一批属性更为方便了。这个例子把 className 以外的所有属性传递给 div 标签：</p></blockquote> <div class="language-javascript line-numbers-mode"><pre class="language-javascript"><code><span class="token keyword">class</span> <span class="token class-name">AutoloadingPostsGrid</span> <span class="token keyword">extends</span> <span class="token class-name">React<span class="token punctuation">.</span>Component</span> <span class="token punctuation">{</span>
    406. 

  406.     <span class="token function">render</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    407. 

  407.         <span class="token keyword">var</span> <span class="token punctuation">{</span>
    408. 

  408.             className<span class="token punctuation">,</span>
    409. 

  409.             <span class="token operator">...</span>others<span class="token punctuation">,</span>
    410. 

  410.         <span class="token punctuation">}</span> <span class="token operator">=</span> <span class="token keyword">this</span><span class="token punctuation">.</span>props<span class="token punctuation">;</span>
    411. 

  411.         <span class="token keyword">return</span> <span class="token punctuation">(</span>
    412. 

  412.             <span class="token operator">&lt;</span>div className<span class="token operator">=</span><span class="token punctuation">{</span>className<span class="token punctuation">}</span><span class="token operator">&gt;</span>
    413. 

  413.                 <span class="token operator">&lt;</span>PostsGrid <span class="token punctuation">{</span><span class="token operator">...</span>others<span class="token punctuation">}</span> <span class="token operator">/</span><span class="token operator">&gt;</span>
    414. 

  414.                 <span class="token operator">&lt;</span>button onClick<span class="token operator">=</span><span class="token punctuation">{</span><span class="token keyword">this</span><span class="token punctuation">.</span>handleOptionsButtonClick<span class="token punctuation">}</span><span class="token operator">&gt;</span>Load more<span class="token operator">&lt;</span><span class="token operator">/</span>button<span class="token operator">&gt;</span>
    415. 

  415.             <span class="token operator">&lt;</span><span class="token operator">/</span>div<span class="token operator">&gt;</span>
    416. 

  416.         <span class="token punctuation">)</span><span class="token punctuation">;</span>
    417. 

  417.     <span class="token punctuation">}</span>
    418. 

  418. <span class="token punctuation">}</span>
    419. 

  419. </code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br></div></div><blockquote><p>下面这种写法，则是传递所有属性的同时，用覆盖新的 className 值：</p></blockquote> <div class="language-javascript line-numbers-mode"><pre class="language-javascript"><code><span class="token operator">&lt;</span>div <span class="token punctuation">{</span><span class="token operator">...</span>this<span class="token punctuation">.</span>props<span class="token punctuation">}</span> className<span class="token operator">=</span><span class="token string">&quot;override&quot;</span><span class="token operator">&gt;</span>
    420. 

  420.   <span class="token operator">...</span>
    421. 

  421. <span class="token operator">&lt;</span><span class="token operator">/</span>div<span class="token operator">&gt;</span>
    422. 

  422. </code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br></div></div><blockquote><p>这个例子则相反，如果属性中没有包含 className，则提供默认的值，而如果属性中已经包含了，则使用属性中的值</p></blockquote> <div class="language-javascript line-numbers-mode"><pre class="language-javascript"><code><span class="token operator">&lt;</span>div className<span class="token operator">=</span><span class="token string">&quot;base&quot;</span> <span class="token punctuation">{</span><span class="token operator">...</span>this<span class="token punctuation">.</span>props<span class="token punctuation">}</span><span class="token operator">&gt;</span>
    423. 

  423.   <span class="token operator">...</span>
    424. 

  424. <span class="token operator">&lt;</span><span class="token operator">/</span>div<span class="token operator">&gt;</span>
    425. 

  425. </code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br></div></div></div> <footer class="page-edit"><!----> <div class="last-updated"><span class="prefix">Last Updated:</span> <span class="time">11/2/2018, 4:24:41 PM</span></div></footer> <div class="page-nav"><p class="inner"><span class="prev">
    426. 

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    427. 

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    428. 

  428.     <script src="/assets/js/app.44a82e39.js" defer></script><script src="/assets/js/3.8ae7454d.js" defer></script><script src="/assets/js/103.f5588224.js" defer></script>
    429. 

  429.   </body>
    430. 

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    431.