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<a href="/react/tips/introduction.html">Introduction</a>
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<a href="/react/tips/props-in-getInitialState-as-anti-pattern.html">Props in getInitialState Is an Anti-Pattern</a>
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<a href="/react/tips/dom-event-listeners.html">DOM Event Listeners in a Component</a>
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<a href="/react/tips/initial-ajax.html">Load Initial Data via AJAX</a>
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<a href="/react/tips/false-in-jsx.html">False in JSX</a>
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<a href="/react/tips/communicate-between-components.html">Communicate Between Components</a>
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<a href="/react/tips/expose-component-functions.html">Expose Component Functions</a>
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<a href="/react/tips/children-undefined.html">this.props.children undefined</a>
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<li>
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<a href="/react/tips/use-react-with-other-libraries.html">Use React with Other Libraries</a>
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<li>
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<a href="/react/tips/dangerously-set-inner-html.html">Dangerously Set innerHTML</a>
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</li>
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</ul>
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</div>
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</div>
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<div class="inner-content">
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<h1>
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React (虚拟) DOM 术语
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<a class="edit-page-link" href="https://github.com/facebook/react/tree/master/docs/docs/ref-10-glossary.zh-CN.md" target="_blank">Edit on GitHub</a>
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</h1>
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<div class="subHeader"></div>
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<p>在 React 的术语中,有五个要重点区分的核心类型:</p>
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<ul>
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<li><a href="#react-elements">ReactElement / ReactElement Factory</a></li>
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<li><a href="#react-nodes">ReactNode</a></li>
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<li><a href="#react-components">ReactComponent / ReactComponent Class</a></li>
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</ul>
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<h2><a class="anchor" name="react-elementsreact-"></a>React Elements(React 元素) <a class="hash-link" href="#react-elementsreact-">#</a></h2>
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<p>React里的首要类型是 <code>ReactElement</code>.它有四个 properties:<code>type</code>, <code>props</code>, <code>key</code> 和 <code>ref</code>.它没有方法,在 prototype 上什么也没有.</p>
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<p>你可以通过 <code>React.createElement</code> 来创建这些对象.</p>
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<div class="highlight"><pre><code class="language-javascript" data-lang="javascript"><span class="kd">var</span> <span class="nx">root</span> <span class="o">=</span> <span class="nx">React</span><span class="p">.</span><span class="nx">createElement</span><span class="p">(</span><span class="s1">'div'</span><span class="p">);</span>
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</code></pre></div>
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<p>要渲染一个新的树到DOM上,你创建 <code>ReactElement</code>s 并传递他们到 <code>ReactDOM.render</code> 伴随着一个标准的 DOM <code>Element</code> (<code>HTMLElement</code> 或 <code>SVGElement</code>).<code>ReactElement</code>s 不要与 DOM <code>Element</code>s 混淆.<code>ReactElement</code> 是一个轻的,有状态的,不可变的,虚拟的DOM <code>Element</code> 的表达.它是一个虚拟 DOM.</p>
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<div class="highlight"><pre><code class="language-javascript" data-lang="javascript"><span class="nx">ReactDOM</span><span class="p">.</span><span class="nx">render</span><span class="p">(</span><span class="nx">root</span><span class="p">,</span> <span class="nb">document</span><span class="p">.</span><span class="nx">getElementById</span><span class="p">(</span><span class="s1">'example'</span><span class="p">));</span>
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</code></pre></div>
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<p>要给一个DOM元素添加 properties,传递一个properties 对象作为第二个参数,第三个参数传递子级.</p>
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<div class="highlight"><pre><code class="language-javascript" data-lang="javascript"><span class="kd">var</span> <span class="nx">child</span> <span class="o">=</span> <span class="nx">React</span><span class="p">.</span><span class="nx">createElement</span><span class="p">(</span><span class="s1">'li'</span><span class="p">,</span> <span class="kc">null</span><span class="p">,</span> <span class="s1">'Text Content'</span><span class="p">);</span>
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<span class="kd">var</span> <span class="nx">root</span> <span class="o">=</span> <span class="nx">React</span><span class="p">.</span><span class="nx">createElement</span><span class="p">(</span><span class="s1">'ul'</span><span class="p">,</span> <span class="p">{</span> <span class="nx">className</span><span class="o">:</span> <span class="s1">'my-list'</span> <span class="p">},</span> <span class="nx">child</span><span class="p">);</span>
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<span class="nx">ReactDOM</span><span class="p">.</span><span class="nx">render</span><span class="p">(</span><span class="nx">root</span><span class="p">,</span> <span class="nb">document</span><span class="p">.</span><span class="nx">getElementById</span><span class="p">(</span><span class="s1">'example'</span><span class="p">));</span>
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</code></pre></div>
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<p>如果你使用 React JSX,这些<code>ReactElement</code>s 已经为你创建了.所以 这是等价的:</p>
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<div class="highlight"><pre><code class="language-javascript" data-lang="javascript"><span class="kd">var</span> <span class="nx">root</span> <span class="o">=</span> <span class="o"><</span><span class="nx">ul</span> <span class="nx">className</span><span class="o">=</span><span class="s2">"my-list"</span><span class="o">></span>
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<span class="o"><</span><span class="nx">li</span><span class="o">></span><span class="nx">Text</span> <span class="nx">Content</span><span class="o"><</span><span class="err">/li></span>
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<span class="o"><</span><span class="err">/ul>;</span>
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<span class="nx">ReactDOM</span><span class="p">.</span><span class="nx">render</span><span class="p">(</span><span class="nx">root</span><span class="p">,</span> <span class="nb">document</span><span class="p">.</span><span class="nx">getElementById</span><span class="p">(</span><span class="s1">'example'</span><span class="p">));</span>
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</code></pre></div><h3><a class="anchor" name="factories"></a>Factories(工厂) <a class="hash-link" href="#factories">#</a></h3>
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<p><code>ReactElement</code>-工厂 是一个产生特定 <code>type</code> property的 <code>ReactElement</code> 的函数.React有一个为你内建的辅助工具来创建工厂.它想这样起作用:</p>
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<div class="highlight"><pre><code class="language-javascript" data-lang="javascript"><span class="kd">function</span> <span class="nx">createFactory</span><span class="p">(</span><span class="nx">type</span><span class="p">)</span> <span class="p">{</span>
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<span class="k">return</span> <span class="nx">React</span><span class="p">.</span><span class="nx">createElement</span><span class="p">.</span><span class="nx">bind</span><span class="p">(</span><span class="kc">null</span><span class="p">,</span> <span class="nx">type</span><span class="p">);</span>
|
|
<span class="p">}</span>
|
|
</code></pre></div>
|
|
<p>它允许你创建一个方便的速记 来代替每次输入 <code>React.createElement('div')</code> .</p>
|
|
<div class="highlight"><pre><code class="language-javascript" data-lang="javascript"><span class="kd">var</span> <span class="nx">div</span> <span class="o">=</span> <span class="nx">React</span><span class="p">.</span><span class="nx">createFactory</span><span class="p">(</span><span class="s1">'div'</span><span class="p">);</span>
|
|
<span class="kd">var</span> <span class="nx">root</span> <span class="o">=</span> <span class="nx">div</span><span class="p">({</span> <span class="nx">className</span><span class="o">:</span> <span class="s1">'my-div'</span> <span class="p">});</span>
|
|
<span class="nx">ReactDOM</span><span class="p">.</span><span class="nx">render</span><span class="p">(</span><span class="nx">root</span><span class="p">,</span> <span class="nb">document</span><span class="p">.</span><span class="nx">getElementById</span><span class="p">(</span><span class="s1">'example'</span><span class="p">));</span>
|
|
</code></pre></div>
|
|
<p>React 已经具备用于常用 HTML tags的内建工厂</p>
|
|
<div class="highlight"><pre><code class="language-javascript" data-lang="javascript"><span class="kd">var</span> <span class="nx">root</span> <span class="o">=</span> <span class="nx">React</span><span class="p">.</span><span class="nx">DOM</span><span class="p">.</span><span class="nx">ul</span><span class="p">({</span> <span class="nx">className</span><span class="o">:</span> <span class="s1">'my-list'</span> <span class="p">},</span>
|
|
<span class="nx">React</span><span class="p">.</span><span class="nx">DOM</span><span class="p">.</span><span class="nx">li</span><span class="p">(</span><span class="kc">null</span><span class="p">,</span> <span class="s1">'Text Content'</span><span class="p">)</span>
|
|
<span class="p">);</span>
|
|
</code></pre></div>
|
|
<p>如果你使用JSX 你没有必要使用工厂.JSX已经为创建 <code>ReactElement</code>s 提供了一个 方便的速记.</p>
|
|
<h2><a class="anchor" name="react-nodes"></a>React Nodes <a class="hash-link" href="#react-nodes">#</a></h2>
|
|
<p>一个 <code>ReactNode</code> 可以是:</p>
|
|
|
|
<ul>
|
|
<li><code>ReactElement</code></li>
|
|
<li><code>string</code> (aka <code>ReactText</code>)</li>
|
|
<li><code>number</code> (aka <code>ReactText</code>)</li>
|
|
<li>Array of <code>ReactNode</code>s (aka <code>ReactFragment</code>)</li>
|
|
</ul>
|
|
|
|
<p>他们被用作其他<code>ReactElement</code>s的properties来表示子级.事实上他们创建了一个 <code>ReactElement</code>s 的树.</p>
|
|
<h2><a class="anchor" name="react-components"></a>React Components <a class="hash-link" href="#react-components">#</a></h2>
|
|
<p>你可以使用 React只使用<code>ReactElement</code>s 但是要真正利用React,你将要使用 <code>ReactComponent</code>s 来创建内嵌 state 的封装.</p>
|
|
|
|
<p>一个 <code>ReactComponent</code> 类就是一个 JavaScript 类 (或者 "constructor function").</p>
|
|
<div class="highlight"><pre><code class="language-javascript" data-lang="javascript"><span class="kd">var</span> <span class="nx">MyComponent</span> <span class="o">=</span> <span class="nx">React</span><span class="p">.</span><span class="nx">createClass</span><span class="p">({</span>
|
|
<span class="nx">render</span><span class="o">:</span> <span class="kd">function</span><span class="p">()</span> <span class="p">{</span>
|
|
<span class="p">...</span>
|
|
<span class="p">}</span>
|
|
<span class="p">});</span>
|
|
</code></pre></div>
|
|
<p>当这个构造函数被调用,期望返回一个至少有一个 <code>render</code> 方法的对象.这个对象被称为一个 <code>ReactComponent</code>.</p>
|
|
<div class="highlight"><pre><code class="language-javascript" data-lang="javascript"><span class="kd">var</span> <span class="nx">component</span> <span class="o">=</span> <span class="k">new</span> <span class="nx">MyComponent</span><span class="p">(</span><span class="nx">props</span><span class="p">);</span> <span class="c1">// never do this</span>
|
|
</code></pre></div>
|
|
<p>与测试不同,你可能通常 <em>绝不会</em> 亲自调用这个构造函数.React 为你调用它.</p>
|
|
|
|
<p>作为替代,你传递 <code>ReactComponent</code> 类到 <code>createElement</code>,你得到一个 <code>ReactElement</code>.</p>
|
|
<div class="highlight"><pre><code class="language-javascript" data-lang="javascript"><span class="kd">var</span> <span class="nx">element</span> <span class="o">=</span> <span class="nx">React</span><span class="p">.</span><span class="nx">createElement</span><span class="p">(</span><span class="nx">MyComponent</span><span class="p">);</span>
|
|
</code></pre></div>
|
|
<p>或者用 JSX:</p>
|
|
<div class="highlight"><pre><code class="language-javascript" data-lang="javascript"><span class="kd">var</span> <span class="nx">element</span> <span class="o">=</span> <span class="o"><</span><span class="nx">MyComponent</span> <span class="o">/></span><span class="p">;</span>
|
|
</code></pre></div>
|
|
<p>当这个被传给 <code>ReactDOM.render</code>,React 会为你调用构造函数并创建一个 <code>ReactComponent</code>,返回给你.</p>
|
|
<div class="highlight"><pre><code class="language-javascript" data-lang="javascript"><span class="kd">var</span> <span class="nx">component</span> <span class="o">=</span> <span class="nx">ReactDOM</span><span class="p">.</span><span class="nx">render</span><span class="p">(</span><span class="nx">element</span><span class="p">,</span> <span class="nb">document</span><span class="p">.</span><span class="nx">getElementById</span><span class="p">(</span><span class="s1">'example'</span><span class="p">));</span>
|
|
</code></pre></div>
|
|
<p>如果你保持用相同类型的 <code>ReactElement</code> 和相同的DOM <code>Element</code>容器调用 <code>ReactDOM.render</code> ,它总是会返回相同的实例.这个实例是状态化的.</p>
|
|
<div class="highlight"><pre><code class="language-javascript" data-lang="javascript"><span class="kd">var</span> <span class="nx">componentA</span> <span class="o">=</span> <span class="nx">ReactDOM</span><span class="p">.</span><span class="nx">render</span><span class="p">(</span><span class="o"><</span><span class="nx">MyComponent</span> <span class="o">/></span><span class="p">,</span> <span class="nb">document</span><span class="p">.</span><span class="nx">getElementById</span><span class="p">(</span><span class="s1">'example'</span><span class="p">));</span>
|
|
<span class="kd">var</span> <span class="nx">componentB</span> <span class="o">=</span> <span class="nx">ReactDOM</span><span class="p">.</span><span class="nx">render</span><span class="p">(</span><span class="o"><</span><span class="nx">MyComponent</span> <span class="o">/></span><span class="p">,</span> <span class="nb">document</span><span class="p">.</span><span class="nx">getElementById</span><span class="p">(</span><span class="s1">'example'</span><span class="p">));</span>
|
|
<span class="nx">componentA</span> <span class="o">===</span> <span class="nx">componentB</span><span class="p">;</span> <span class="c1">// true</span>
|
|
</code></pre></div>
|
|
<p>这就是为什么你不应该构造你自己的实例.作为替代,<code>ReactElement</code> 在它被构造以前 是一个虚拟的 <code>ReactComponent</code>.一个老的和新的<code>ReactElement</code> 可以被比较来判断 一个新的 <code>ReactComponent</code> 实例是否需要被创建或者已经存在的是否应该被重用.</p>
|
|
|
|
<p><code>ReactComponent</code> 的 <code>render</code> 方法被期望返回另一个 <code>ReactElement</code>.这允许这些组件被结构化.最后,渲染分解为 带着一个 <code>string</code> tag的<code>ReactElement</code>,它实例化一个 DOM <code>Element</code> 实例并把它插入document里.</p>
|
|
<h2><a class="anchor" name="formal-type-definitions"></a>Formal Type Definitions <a class="hash-link" href="#formal-type-definitions">#</a></h2><h3><a class="anchor" name="entry-point"></a>Entry Point <a class="hash-link" href="#entry-point">#</a></h3><div class="highlight"><pre><code class="language-text" data-lang="text">ReactDOM.render = (ReactElement, HTMLElement | SVGElement) => ReactComponent;
|
|
</code></pre></div><h3><a class="anchor" name="nodes-and-elements"></a>Nodes and Elements <a class="hash-link" href="#nodes-and-elements">#</a></h3><div class="highlight"><pre><code class="language-text" data-lang="text">type ReactNode = ReactElement | ReactFragment | ReactText;
|
|
|
|
type ReactElement = ReactComponentElement | ReactDOMElement;
|
|
|
|
type ReactDOMElement = {
|
|
type : string,
|
|
props : {
|
|
children : ReactNodeList,
|
|
className : string,
|
|
etc.
|
|
},
|
|
key : string | boolean | number | null,
|
|
ref : string | null
|
|
};
|
|
|
|
type ReactComponentElement<TProps> = {
|
|
type : ReactClass<TProps>,
|
|
props : TProps,
|
|
key : string | boolean | number | null,
|
|
ref : string | null
|
|
};
|
|
|
|
type ReactFragment = Array<ReactNode | ReactEmpty>;
|
|
|
|
type ReactNodeList = ReactNode | ReactEmpty;
|
|
|
|
type ReactText = string | number;
|
|
|
|
type ReactEmpty = null | undefined | boolean;
|
|
</code></pre></div><h3><a class="anchor" name="classes-and-components"></a>Classes and Components <a class="hash-link" href="#classes-and-components">#</a></h3><div class="highlight"><pre><code class="language-text" data-lang="text">type ReactClass<TProps> = (TProps) => ReactComponent<TProps>;
|
|
|
|
type ReactComponent<TProps> = {
|
|
props : TProps,
|
|
render : () => ReactElement
|
|
};
|
|
</code></pre></div>
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