uTools-Manuals/docs/javascript/Reference/Global_Objects/Array/some.html

<article id="wikiArticle">
<div></div>
<p><code><strong>some()</strong></code> 方法测试是否至少有一个元素通过由提供的函数实现的测试。</p>
<div class="note">
<p><strong>注意：</strong>对于放在空数组上的任何条件，此方法返回<code>false</code>。</p>
</div>
<div><iframe class="interactive interactive-js" frameborder="0" height="250" src="https://interactive-examples.mdn.mozilla.net/pages/js/array-some.html" width="100%"></iframe></div>
<h2 id="Syntax" name="Syntax">语法</h2>
<pre class="syntaxbox"><code><em>arr</em>.some(<em>callback(element[, index[, array]])[, thisArg]</em>)</code></pre>
<h3 id="Parameters" name="Parameters">参数</h3>
<dl>
<dt><code>callback</code></dt>
<dd>用来测试每个元素的函数，接受三个参数：
 <dl>
<dt><code>element</code></dt>
<dd>数组中正在处理的元素。</dd>
<dt><code>index</code> <span class="inlineIndicator optional optionalInline">可选</span></dt>
<dd>数组中正在处理的元素的索引值。</dd>
<dt><code>array</code><span class="inlineIndicator optional optionalInline">可选</span></dt>
<dd><code>some()</code>被调用的数组。</dd>
</dl>
</dd>
<dt><code>thisArg</code><span class="inlineIndicator optional optionalInline">可选</span></dt>
<dd>执行 <code>callback</code> 时使用的 <code>this</code> 值。</dd>
</dl>
<h3 id="返回值">返回值</h3>
<p>如果回调函数返回任何数组元素的<a class="glossaryLink" href="/en-US/docs/Glossary/truthy" title='truthy: In JavaScript, a truthy value is a value that is considered  true when encountered in a Boolean context. All values are truthy unless they are defined as falsy (i.e., except for false, 0, "", null, undefined, and NaN).'>truthy</a>值，则返回<strong><code>true</code></strong>；否则为<code><strong>false</strong></code>。</p>
<h2 id="Description" name="Description">描述</h2>
<p><code>some()</code> 为数组中的每一个元素执行一次 <code>callback</code> 函数，直到找到一个使得 callback 返回一个“真值”（即可转换为布尔值 true 的值）。如果找到了这样一个值，<code>some()</code> 将会立即返回 <code>true</code>。否则，<code>some()</code> 返回 <code>false</code>。<code>callback</code> 只会在那些”有值“的索引上被调用，不会在那些被删除或从来未被赋值的索引上调用。</p>
<p><code style="font-style: normal; line-height: 1.5;">callback</code><span style="line-height: 1.5;"> 被调用时传入三个参数：元素的值，元素的索引，被遍历的数组。</span></p>
<p>将会把它传给被调用的 <code>callback</code>，作为 <code>this</code> 值。否则，在非严格模式下将会是全局对象，严格模式下是 <code>undefined</code>。</p>
<p><code>some()</code> 被调用时不会改变数组。</p>
<p><code>some()</code> 遍历的元素的范围在第一次调用 <code>callback</code>. 时就已经确定了。在调用 <code>some()</code> 后被添加到数组中的值不会被 <code>callback</code> 访问到。如果数组中存在且还未被访问到的元素被 <code>callback</code> 改变了，则其传递给 <code>callback</code> 的值是 <code>some()</code> 访问到它那一刻的值。</p>
<h2 id="Examples" name="Examples">示例</h2>
<h3 id="Example:_Testing_size_of_all_array_elements" name="Example:_Testing_size_of_all_array_elements">测试数组元素的值</h3>
<p>下面的例子检测在数组中是否有元素大于 10。</p>
<p> </p>
<pre class="brush: js">function isBiggerThan10(element, index, array) {
  return element &gt; 10;
}

[2, 5, 8, 1, 4].some(isBiggerThan10);  // false
[12, 5, 8, 1, 4].some(isBiggerThan10); // true</pre>
<h3 id="使用箭头函数测试数组元素的值">使用箭头函数测试数组元素的值</h3>
<p><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/Arrow_functions">箭头函数</a> 可以通过更简洁的语法实现相同的用例.</p>
<pre class="brush: js"><code>[2, 5, 8, 1, 4].some(x =&gt; x &gt; 10);  // false
[12, 5, 8, 1, 4].some(x =&gt; x &gt; 10); // true</code></pre>
<h3 id="判断数组元素中是否存在某个值">判断数组元素中是否存在某个值</h3>
<p>此例中为模仿 <code>includes()</code>  方法, 若元素在数组中存在, 则回调函数返回值为 <code>true</code> :</p>
<pre class="brush: js">var fruits = ['apple', 'banana', 'mango', 'guava'];

function checkAvailability(arr, val) {
  return arr.some(function(arrVal) {
    return val === arrVal;
  });
}

checkAvailability(fruits, 'kela');   // false
checkAvailability(fruits, 'banana'); // true</pre>
<h3 id="使用箭头函数判断数组元素中是否存在某个值">使用箭头函数判断数组元素中是否存在某个值</h3>
<pre class="brush: js">var fruits = ['apple', 'banana', 'mango', 'guava'];

function checkAvailability(arr, val) {
  return arr.some(arrVal =&gt; val === arrVal);
}

checkAvailability(fruits, 'kela');   // false
checkAvailability(fruits, 'banana'); // true</pre>
<h3 id="将任意值转换为布尔类型">将任意值转换为布尔类型</h3>
<pre class="brush: js">var TRUTHY_VALUES = [true, 'true', 1];

function getBoolean(value) {
  'use strict';
   
  if (typeof value === 'string') { 
    value = value.toLowerCase().trim();
  }

  return TRUTHY_VALUES.some(function(t) {
    return t === value;
  });
}

getBoolean(false);   // false
getBoolean('false'); // false
getBoolean(1);       // true
getBoolean('true');  // true
</pre>
<h2 id="Compatibility" name="Compatibility">Polyfill</h2>
<p>在第 5 版时，<code>some()</code> 被添加进 ECMA-262 标准；这样导致某些实现环境可能不支持它。你可以把下面的代码插入到脚本的开头来解决此问题，从而允许在那些没有原生支持它的实现环境中使用它。该算法是 ECMA-262 第 5 版中指定的算法，假定 <code>Object </code>和 <code>TypeError</code> 拥有他们的初始值，且 <code>fun.call</code> 等价于 <code><a href="Reference/Global_Objects/Function/call" title="call() 方法调用一个函数, 其具有一个指定的this值和分别地提供的参数(参数的列表)。"><code>Function.prototype.call</code></a></code>。</p>
<pre class="brush: js">// Production steps of ECMA-262, Edition 5, 15.4.4.17
// Reference: http://es5.github.io/#x15.4.4.17
if (!Array.prototype.some) {
  Array.prototype.some = function(fun/*, thisArg*/) {
    'use strict';

    if (this == null) {
      throw new TypeError('Array.prototype.some called on null or undefined');
    }

    if (typeof fun !== 'function') {
      throw new TypeError();
    }

    var t = Object(this);
    var len = t.length &gt;&gt;&gt; 0;

    var thisArg = arguments.length &gt;= 2 ? arguments[1] : void 0;
    for (var i = 0; i &lt; len; i++) {
      if (i in t &amp;&amp; fun.call(thisArg, t[i], i, t)) {
        return true;
      }
    }

    return false;
  };
}</pre>
<h2 id="规范">规范</h2>
<table class="standard-table">
<tbody>
<tr>
<th scope="col">Specification</th>
<th scope="col">Status</th>
<th scope="col">Comment</th>
</tr>
<tr>
<td><a class="external" href="https://www.ecma-international.org/ecma-262/5.1/#sec-15.4.4.17" hreflang="en" lang="en" rel="noopener">ECMAScript 5.1 (ECMA-262)<br/><small lang="zh-CN">Array.prototype.some</small></a></td>
<td><span class="spec-Standard">Standard</span></td>
<td>Initial definition. Implemented in JavaScript 1.6.</td>
</tr>
<tr>
<td><a class="external" href="https://www.ecma-international.org/ecma-262/6.0/#sec-array.prototype.some" hreflang="en" lang="en" rel="noopener">ECMAScript 2015 (6th Edition, ECMA-262)<br/><small lang="zh-CN">Array.prototype.some</small></a></td>
<td><span class="spec-Standard">Standard</span></td>
<td> </td>
</tr>
<tr>
<td><a class="external" href="https://tc39.github.io/ecma262/#sec-array.prototype.some" hreflang="en" lang="en" rel="noopener">ECMAScript Latest Draft (ECMA-262)<br/><small lang="zh-CN">Array.prototype.some</small></a></td>
<td><span class="spec-Draft">Draft</span></td>
<td> </td>
</tr>
</tbody>
</table>
<h2 id="浏览器兼容">浏览器兼容</h2>
<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>some</code></th><td class="bc-supports-yes bc-browser-chrome"><span class="bc-browser-name">Chrome</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
              Yes</td><td class="bc-supports-yes bc-browser-edge"><span class="bc-browser-name">Edge</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
              12</td><td class="bc-supports-yes bc-browser-firefox"><span class="bc-browser-name">Firefox</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
              1.5</td><td class="bc-supports-yes bc-browser-ie"><span class="bc-browser-name">IE</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
              9</td><td class="bc-supports-yes bc-browser-opera"><span class="bc-browser-name">Opera</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
              Yes</td><td class="bc-supports-yes bc-browser-safari"><span class="bc-browser-name">Safari</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
              Yes</td><td class="bc-supports-yes bc-browser-webview_android"><span class="bc-browser-name">WebView Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
              Yes</td><td class="bc-supports-yes bc-browser-chrome_android"><span class="bc-browser-name">Chrome Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
              Yes</td><td class="bc-supports-yes bc-browser-edge_mobile"><span class="bc-browser-name">Edge Mobile</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
              Yes</td><td class="bc-supports-yes bc-browser-firefox_android"><span class="bc-browser-name">Firefox Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
              4</td><td class="bc-supports-yes bc-browser-opera_android"><span class="bc-browser-name">Opera Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
              Yes</td><td class="bc-supports-yes bc-browser-safari_ios"><span class="bc-browser-name">Safari iOS</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
              Yes</td><td class="bc-supports-yes bc-browser-samsunginternet_android"><span class="bc-browser-name">Samsung Internet Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
              Yes</td><td class="bc-supports-yes bc-browser-nodejs"><span class="bc-browser-name">nodejs</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
              Yes</td></tr></tbody></table><section class="bc-legend" id="sect1"><h3 class="offscreen" id="Legend">Legend</h3><dl><dt><span class="bc-supports-yes bc-supports">
<abbr class="bc-level bc-level-yes only-icon" title="Full support">
<span>Full support</span>
                  
                </abbr></span></dt><dd>Full support</dd></dl></section></div><p></p>
</div>
<h2 id="See_also" name="See_also">相关链接</h2>
<ul>
<li><a href="Reference/Global_Objects/Array/find" title="find() 方法返回数组中满足提供的测试函数的第一个元素的值。否则返回 undefined。"><code>Array.prototype.find()</code></a></li>
<li><a href="Reference/Global_Objects/Array/forEach" title="forEach() 方法对数组的每个元素执行一次提供的函数。"><code>Array.prototype.forEach()</code></a></li>
<li><a href="Reference/Global_Objects/Array/every" title="every() 方法测试数组的所有元素是否都通过了指定函数的测试。"><code>Array.prototype.every()</code></a></li>
<li><a href="Reference/Global_Objects/TypedArray/some" title="这个 some() 方法检测 TypedArray 的一些元素是否通过所提供函数的测试. 这个方法和 Array.prototype.some() 相同. TypedArray 是 typed array types 之一."><code>TypedArray.prototype.some()</code></a></li>
</ul>
</article>