mirror of
https://github.com/fofolee/uTools-Manuals.git
synced 2025-06-08 23:14:06 +08:00
110 lines
11 KiB
HTML
110 lines
11 KiB
HTML
<article id="wikiArticle">
|
||
<div><div class="blockIndicator obsolete obsoleteHeader"><p><strong><span class="icon-only-inline" title="This is an obsolete API and is no longer guaranteed to work."><i class="icon-trash"> </i></span> 已废弃</strong><br/>This feature is obsolete. Although it may still work in some browsers, its use is discouraged since it could be removed at any time. Try to avoid using it.</p></div></div>
|
||
<p><strong>Array.observe()</strong> 方法用于异步监视数组发生的变化，类似于针对对象的 <a href="Reference/Global_Objects/Object/observe" title="Object.observe() 方法用于异步地监视一个对象的修改。当对象属性被修改时，方法的回调函数会提供一个有序的修改流。然而，这个接口已经被废弃并从各浏览器中移除。你可以使用更通用的 Proxy 对象替代。"><code>Object.observe()</code></a> 。当数组的值发生变化时，它按发生顺序提供了一个变化流。与 <code>Object.observe()</code> 类似，它由如下可接受的变化类型列表<code>["add"、"update"、"delete"、"splice"]</code>触发。</p>
|
||
<h2 id="语法">语法</h2>
|
||
<pre><code class="language-javascript"><code>Array.observe(<var>arr</var>, <var>callback</var>)</code></code></pre>
|
||
<h3 id="参数">参数</h3>
|
||
<dl>
|
||
<dt><code>arr</code></dt>
|
||
<dd>用于被监视的数组</dd>
|
||
<dt><code>callback</code></dt>
|
||
<dd>每当数组发生变化时，使用如下参数调用该函数：
|
||
<dl>
|
||
<dt><code>changes</code></dt>
|
||
<dd>用于表示变化的对象数组。每个变化对象的属性如下：
|
||
<ul>
|
||
<li><strong><code>name</code></strong>: 变化的属性名。</li>
|
||
<li><strong><code>object</code></strong>: 变化后的数组。</li>
|
||
<li><strong><code>type</code></strong>: 用于表示变化类型的字符串。<code>其取值为"add"、</code><code>"update"、</code><code>"delete"</code>或 <code>"splice"</code>之一。</li>
|
||
<li><strong><code>oldValue</code></strong>: 仅用于<code>"update"</code>和<code>"delete"类型。变化</code>之前的取值。</li>
|
||
<li><strong><code>index</code></strong>: <code>仅用于"splice"类型。</code>变化发生所在索引。</li>
|
||
<li><strong><code>removed</code></strong>: 仅用于<code>"splice"类型。</code>被删除元素组成的数组。</li>
|
||
<li><strong><code>addedCount</code></strong>: 仅用于<code>"splice"</code>类型。被添加的元素数量。</li>
|
||
</ul>
|
||
</dd>
|
||
</dl>
|
||
</dd>
|
||
</dl>
|
||
<h2 id="描述">描述</h2>
|
||
<p>每次 arr 发生任何变化时，回调函数将被调用，调用参数为所有变化按发生顺序组成的数组。</p>
|
||
<div class="note">
|
||
<p>通过Array方法如<a href="https://developer.mozilla.orgReference/Global_Objects/Array/pop"> Array.prototype.pop( )</a> 触发的变化将被报告成"<em>splice</em>"变化，长度不变但索引赋值发生变化的将被报告成"update"变化。</p>
|
||
</div>
|
||
<h2 id="示例">示例</h2>
|
||
<h3 id="Example_Logging_different_change_types">Example: Logging different change types</h3>
|
||
<pre><code class="language-javascript">var arr = ['a', 'b', 'c'];
|
||
|
||
Array.observe(arr, function(changes) {
|
||
console.log(changes);
|
||
});
|
||
|
||
arr[1] = 'B';
|
||
// [{type: 'update', object: <arr>, name: '1', oldValue: 'b'}]
|
||
|
||
arr[3] = 'd';
|
||
// [{type: 'splice', object: <arr>, index: 3, removed: [], addedCount: 1}]
|
||
|
||
arr.splice(1, 2, 'beta', 'gamma', 'delta');
|
||
// [{type: 'splice', object: <arr>, index: 1, removed: ['B', 'c'], addedCount: 3}]
|
||
</code></pre>
|
||
<h2 id="Specifications" name="Specifications">标准规范</h2>
|
||
<p><a class="external" href="https://github.com/arv/ecmascript-object-observe" rel="noopener">Strawman proposal specification</a>.</p>
|
||
<h2 id="Browser_compatibility" name="Browser_compatibility">浏览器支持</h2>
|
||
<div>
|
||
<div>
|
||
<div class="hidden">The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out <a class="external" href="https://github.com/mdn/browser-compat-data" rel="noopener">https://github.com/mdn/browser-compat-data</a> and send us a pull request.</div>
|
||
<p></p><div class="bc-data"><a class="bc-github-link external" href="https://github.com/mdn/browser-compat-data" rel="noopener">Update compatibility data on GitHub</a><table class="bc-table bc-table-js"><thead><tr class="bc-platforms"><td></td><th class="bc-platform-desktop" colspan="6"><span>Desktop</span></th><th class="bc-platform-mobile" colspan="7"><span>Mobile</span></th><th class="bc-platform-server" colspan="1"><span>Server</span></th></tr><tr class="bc-browsers"><td></td><th class="bc-browser-chrome"><span class="bc-head-txt-label bc-head-icon-chrome">Chrome</span></th><th class="bc-browser-edge"><span class="bc-head-txt-label bc-head-icon-edge">Edge</span></th><th class="bc-browser-firefox"><span class="bc-head-txt-label bc-head-icon-firefox">Firefox</span></th><th class="bc-browser-ie"><span class="bc-head-txt-label bc-head-icon-ie">Internet Explorer</span></th><th class="bc-browser-opera"><span class="bc-head-txt-label bc-head-icon-opera">Opera</span></th><th class="bc-browser-safari"><span class="bc-head-txt-label bc-head-icon-safari">Safari</span></th><th class="bc-browser-webview_android"><span class="bc-head-txt-label bc-head-icon-webview_android">Android webview</span></th><th class="bc-browser-chrome_android"><span class="bc-head-txt-label bc-head-icon-chrome_android">Chrome for Android</span></th><th class="bc-browser-edge_mobile"><span class="bc-head-txt-label bc-head-icon-edge_mobile">Edge Mobile</span></th><th class="bc-browser-firefox_android"><span class="bc-head-txt-label bc-head-icon-firefox_android">Firefox for Android</span></th><th class="bc-browser-opera_android"><span class="bc-head-txt-label bc-head-icon-opera_android">Opera for Android</span></th><th class="bc-browser-safari_ios"><span class="bc-head-txt-label bc-head-icon-safari_ios">Safari on iOS</span></th><th class="bc-browser-samsunginternet_android"><span class="bc-head-txt-label bc-head-icon-samsunginternet_android">Samsung Internet</span></th><th class="bc-browser-nodejs"><span class="bc-head-txt-label bc-head-icon-nodejs">Node.js</span></th></tr></thead><tbody><tr><th scope="row"><code>observe</code> <div class="bc-icons"><abbr class="only-icon" title="Deprecated. Not for use in new websites."><span>Deprecated</span><i class="ic-deprecated"></i></abbr><abbr class="only-icon" title="Non-standard. Expect poor cross-browser support."><span>Non-standard</span><i class="ic-non-standard"></i></abbr></div></th><td class="bc-supports-no bc-browser-chrome"><span class="bc-browser-name">Chrome</span><abbr class="bc-level-no only-icon" title="No support">
|
||
<span>No support</span>
|
||
</abbr>36 — 52</td><td class="bc-supports-no bc-browser-edge"><span class="bc-browser-name">Edge</span><abbr class="bc-level-no only-icon" title="No support">
|
||
<span>No support</span>
|
||
</abbr>
|
||
No</td><td class="bc-supports-no bc-browser-firefox"><span class="bc-browser-name">Firefox</span><abbr class="bc-level-no only-icon" title="No support">
|
||
<span>No support</span>
|
||
</abbr>
|
||
No</td><td class="bc-supports-no bc-browser-ie"><span class="bc-browser-name">IE</span><abbr class="bc-level-no only-icon" title="No support">
|
||
<span>No support</span>
|
||
</abbr>
|
||
No</td><td class="bc-supports-no bc-browser-opera"><span class="bc-browser-name">Opera</span><abbr class="bc-level-no only-icon" title="No support">
|
||
<span>No support</span>
|
||
</abbr>
|
||
No</td><td class="bc-supports-no bc-browser-safari"><span class="bc-browser-name">Safari</span><abbr class="bc-level-no only-icon" title="No support">
|
||
<span>No support</span>
|
||
</abbr>
|
||
No</td><td class="bc-supports-no bc-browser-webview_android"><span class="bc-browser-name">WebView Android</span><abbr class="bc-level-no only-icon" title="No support">
|
||
<span>No support</span>
|
||
</abbr>
|
||
No</td><td class="bc-supports-no bc-browser-chrome_android"><span class="bc-browser-name">Chrome Android</span><abbr class="bc-level-no only-icon" title="No support">
|
||
<span>No support</span>
|
||
</abbr>
|
||
No</td><td class="bc-supports-no bc-browser-edge_mobile"><span class="bc-browser-name">Edge Mobile</span><abbr class="bc-level-no only-icon" title="No support">
|
||
<span>No support</span>
|
||
</abbr>
|
||
No</td><td class="bc-supports-no bc-browser-firefox_android"><span class="bc-browser-name">Firefox Android</span><abbr class="bc-level-no only-icon" title="No support">
|
||
<span>No support</span>
|
||
</abbr>
|
||
No</td><td class="bc-supports-no bc-browser-opera_android"><span class="bc-browser-name">Opera Android</span><abbr class="bc-level-no only-icon" title="No support">
|
||
<span>No support</span>
|
||
</abbr>
|
||
No</td><td class="bc-supports-no bc-browser-safari_ios"><span class="bc-browser-name">Safari iOS</span><abbr class="bc-level-no only-icon" title="No support">
|
||
<span>No support</span>
|
||
</abbr>
|
||
No</td><td class="bc-supports-no bc-browser-samsunginternet_android"><span class="bc-browser-name">Samsung Internet Android</span><abbr class="bc-level-no only-icon" title="No support">
|
||
<span>No support</span>
|
||
</abbr>
|
||
No</td><td class="bc-supports-no bc-browser-nodejs"><span class="bc-browser-name">nodejs</span><abbr class="bc-level-no only-icon" title="No support">
|
||
<span>No support</span>
|
||
</abbr>
|
||
No</td></tr></tbody></table><section class="bc-legend" id="sect1"><h3 class="offscreen" id="Legend">Legend</h3><dl><dt><span class="bc-supports-no bc-supports">
|
||
<abbr class="bc-level bc-level-no only-icon" title="No support">
|
||
<span>No support</span>
|
||
|
||
</abbr></span></dt><dd>No support</dd><dt><abbr class="only-icon" title="Non-standard. Expect poor cross-browser support."><span>Non-standard. Expect poor cross-browser support.</span><i class="ic-non-standard"></i></abbr></dt><dd>Non-standard. Expect poor cross-browser support.</dd><dt><abbr class="only-icon" title="Deprecated. Not for use in new websites."><span>Deprecated. Not for use in new websites.</span><i class="ic-deprecated"></i></abbr></dt><dd>Deprecated. Not for use in new websites.</dd></dl></section></div><p></p>
|
||
</div>
|
||
</div>
|
||
<h2 id="See_also" name="See_also">相关内容</h2>
|
||
<ul>
|
||
<li><a href="Reference/Global_Objects/Array/unobserve" title="Array.unobserve()方法用来移除Array.observe()设置的所有观察者。"><code>Array.unobserve()</code></a> <span title="这是一个实验性的 API，请尽量不要在生产环境中使用它。"><i class="icon-beaker"> </i></span></li>
|
||
<li><a href="Reference/Global_Objects/Object/observe" title="Object.observe() 方法用于异步地监视一个对象的修改。当对象属性被修改时，方法的回调函数会提供一个有序的修改流。然而，这个接口已经被废弃并从各浏览器中移除。你可以使用更通用的 Proxy 对象替代。"><code>Object.observe()</code></a> <span title="这是一个实验性的 API，请尽量不要在生产环境中使用它。"><i class="icon-beaker"> </i></span></li>
|
||
<li><a class="external" href="https://stackoverflow.com/q/29269057/778272" rel="noopener">Under what condition would Array.observe's “add” event trigger?</a></li>
|
||
</ul>
|
||
</article> |