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<article id="wikiArticle">
<div class="blockIndicator note">
<p> </p>
</div>
<p></p><p></p>
<p id="概述"><strong>Promise </strong>对象用于表示一个异步操作的最终状态(完成或失败),以及该异步操作的结果值。</p>
<div class="note">
<p>本条目为Promise构造函数。想要了解promises请首先阅读 <a href="Guide/Using_promises">使用 promises</a>。构造函数主要是用来包装还未支持promises的函数。</p>
</div>
<div><iframe class="interactive interactive-js" frameborder="0" height="250" src="https://interactive-examples.mdn.mozilla.net/pages/js/promise-constructor.html" width="100%"></iframe></div>
<p class="hidden">The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone <a class="external" href="https://github.com/mdn/interactive-examples" rel="noopener">https://github.com/mdn/interactive-examples</a> and send us a pull request.</p>
<h2 id="语法">语法</h2>
<pre><code class="language-javascript">new Promise( function(resolve, reject) {...} /* executor */ );</code></pre>
<h3 id="参数">参数</h3>
<dl>
<dt>executor</dt>
<dd>executor是带有 <code>resolve</code> 和 <code>reject</code> 两个参数的函数 。Promise构造函数<font face="consolas, Liberation Mono, courier, monospace">执行时立即调用</font><code>executor</code> 函数, <code>resolve</code> 和 <code>reject</code> 两个函数作为参数传递给<code>executor</code>executor 函数在Promise构造函数返回所建promise实例对象前被调用<code>resolve</code> 和 <code>reject</code> 函数被调用时分别将promise的状态改为<em>fulfilled</em>完成或rejected失败。executor 内部通常会执行一些异步操作,一旦异步操作执行完毕(可能成功/失败)要么调用resolve函数来将promise状态改成<em>fulfilled</em>,要么调用<code>reject</code> 函数将promise的状态改为rejected。如果在executor函数中抛出一个错误那么该promise 状态为rejected。executor函数的返回值被忽略。</dd>
</dl>
<h2 id="描述">描述</h2>
<p><code><strong>Promise</strong></code> 对象是一个代理对象代理一个值被代理的值在Promise对象创建时可能是未知的。它允许你为异步操作的成功和失败分别绑定相应的处理方法handlers。 这让异步方法可以像同步方法那样返回值但并不是立即返回最终执行结果而是一个能代表未来出现的结果的promise对象</p>
<p>一个 <code>Promise</code>有以下几种状态:</p>
<ul>
<li><em>pending</em>: 初始状态,既不是成功,也不是失败状态。</li>
<li><em>fulfilled</em>: 意味着操作成功完成。</li>
<li><em>rejected</em>: 意味着操作失败。</li>
</ul>
<p>pending 状态的 Promise 对象可能会变为fulfilled 状态并传递一个值给相应的状态处理方法也可能变为失败状态rejected并传递失败信息。当其中任一种情况出现时Promise 对象的 <code>then</code> 方法绑定的处理方法<span style="line-height: 1.5;"></span>handlers <span style="line-height: 1.5;">就会被调用then方法包含两个参数onfulfilled 和 onrejected它们都是 Function 类型。当Promise状态为</span><em>fulfilled</em><span style="line-height: 1.5;">时,调用 then 的 onfulfilled 方法当Promise状态为</span><em>rejected</em><span style="line-height: 1.5;">时,调用 then 的 onrejected 方法, 所以在异步操作的完成和绑定处理方法之间不存在竞争)。</span></p>
<p>因为 <span style="font-family: consolas,monaco,andale mono,monospace;"><code><a href="Reference/Global_Objects/Promise/then" title="then() 方法返回一个  Promise 。它最多需要有两个参数Promise 的成功和失败情况的回调函数。"><code>Promise.prototype.then</code></a></code> </span>和  <code style="font-style: normal;"><a href="Reference/Global_Objects/Promise/catch" title="catch() 方法返回一个Promise并且处理拒绝的情况。它的行为与调用Promise.prototype.then(undefined, onRejected) 相同。 (事实上, calling obj.catch(onRejected) 内部calls obj.then(undefined, onRejected))."><code>Promise.prototype.catch</code></a></code> 方法返回promise 对象, 所以它们可以被链式调用。</p>
<p><img alt="" src="https://mdn.mozillademos.org/files/8633/promises.png" style="height: 297px; width: 801px;"/></p>
<div class="note">
<p><strong>不要和惰性求值混淆:</strong> 有一些语言中有惰性求值和延时计算的特性它们也被称为“promises”例如Scheme. Javascript中的promise代表一种已经发生的状态 而且可以通过回调方法链在一起。 如果你想要的是表达式的延时计算,考虑无参数的"<a href="Reference/Functions/Arrow_functions">箭头方法</a>":  <code>f = () =&gt;</code><em><code>表达式</code> </em>创建惰性求值的表达式<em></em>使用 <code>f()</code><strong> </strong>求值。</p>
</div>
<div class="note">
<p><strong>注意:</strong> 如果一个promise对象处在fulfilled或rejected状态而不是pending状态那么它也可以被称为<em>settled</em>状态。你可能也会听到一个术语<em>resolved</em> 它表示promise对象处于fulfilled状态。关于promise的术语 Domenic Denicola 的 <a class="external" href="https://github.com/domenic/promises-unwrapping/blob/master/docs/states-and-fates.md" rel="noopener">States and fates</a> 有更多详情可供参考。</p>
</div>
<h2 id="属性">属性</h2>
<dl>
<dt><code>Promise.length</code></dt>
<dd>length属性其值总是为 1 (构造器参数的数目).</dd>
<dt><a href="Reference/Global_Objects/Promise/prototype" title="Promise.prototype 属性表示 Promise 构造器的原型."><code>Promise.prototype</code></a></dt>
<dd>表示 <code>Promise</code> 构造器的原型.</dd>
</dl>
<h2 id="方法">方法</h2>
<dl>
<dt><a href="Reference/Global_Objects/Promise/all" title="Promise.all(iterable) 方法返回一个 Promise 实例此实例在 iterable 参数内所有的 promise 都“完成resolved”或参数中不包含 promise 时回调完成resolve如果参数中  promise 有一个失败rejected此实例回调失败reject失败原因的是第一个失败 promise 的结果。"><code>Promise.all(iterable)</code></a></dt>
<dd>这个方法返回一个新的promise对象该promise对象在iterable参数对象里所有的promise对象都成功的时候才会触发成功一旦有任何一个iterable里面的promise对象失败则立即触发该promise对象的失败。这个新的promise对象在触发成功状态以后会把一个包含iterable里所有promise返回值的数组作为成功回调的返回值顺序跟iterable的顺序保持一致如果这个新的promise对象触发了失败状态它会把iterable里第一个触发失败的promise对象的错误信息作为它的失败错误信息。Promise.all方法常被用于处理多个promise对象的状态集合。可以参考jQuery.when方法---译者注)</dd>
<dt><a href="Reference/Global_Objects/Promise/race" title="Promise.race(iterable) 方法返回一个 promise一旦迭代器中的某个promise解决或拒绝返回的 promise就会解决或拒绝。"><code>Promise.race(iterable)</code></a></dt>
<dd>当iterable参数里的任意一个子promise被成功或失败后父promise马上也会用子promise的成功返回值或失败详情作为参数调用父promise绑定的相应句柄并返回该promise对象。</dd>
</dl>
<dl>
<dt><a href="Reference/Global_Objects/Promise/reject" title="Promise.reject(reason)方法返回一个带有拒绝原因reason参数的Promise对象。"><code>Promise.reject(reason)</code></a></dt>
<dd>返回一个状态为失败的Promise对象并将给定的失败信息传递给对应的处理方法</dd>
</dl>
<dl>
<dt><a href="Reference/Global_Objects/Promise/resolve" title="The source for this interactive demo is stored in a GitHub repository. If you'd like to contribute to the interactive demo project, please clone https://github.com/mdn/interactive-examples and send us a pull request."><code>Promise.resolve(value)</code></a></dt>
<dd>返回一个状态由给定value决定的Promise对象。如果该值是thenable(即带有then方法的对象)返回的Promise对象的最终状态由then方法执行决定否则的话(该value为空基本类型或者不带then方法的对象),返回的Promise对象状态为fulfilled并且将该value传递给对应的then方法。通常而言如果你不知道一个值是否是Promise对象使用Promise.resolve(value) 来返回一个Promise对象,这样就能将该value以Promise对象形式使用。</dd>
</dl>
<h2 id="Promise_原型">Promise 原型</h2>
<h3 id="属性_2">属性</h3>
<p></p><dl>
<dt><code>Promise.prototype.constructor</code></dt>
<dd>返回被创建的实例函数.  默认为 <a href="Reference/Global_Objects/Promise" title="Promise 对象用于表示一个异步操作的最终状态完成或失败以及其返回的值。"><code>Promise</code></a> 函数.</dd>
</dl><p></p>
<h3 id="方法_2">方法</h3>
<p></p><dl>
<dt><a href="Reference/Global_Objects/Promise/catch" title="catch() 方法返回一个Promise并且处理拒绝的情况。它的行为与调用Promise.prototype.then(undefined, onRejected) 相同。 (事实上, calling obj.catch(onRejected) 内部calls obj.then(undefined, onRejected))."><code>Promise.prototype.catch(onRejected)</code></a></dt>
<dd>添加一个拒绝(rejection) 回调到当前 promise, 返回一个新的promise。当这个回调函数被调用新 promise 将以它的返回值来resolve否则如果当前promise 进入fulfilled状态则以当前promise的完成结果作为新promise的完成结果.</dd>
<dt><a href="Reference/Global_Objects/Promise/then" title="then() 方法返回一个  Promise 。它最多需要有两个参数Promise 的成功和失败情况的回调函数。"><code>Promise.prototype.then(onFulfilled, onRejected)</code></a></dt>
<dd>添加解决(fulfillment)和拒绝(rejection)回调到当前 promise, 返回一个新的 promise, 将以回调的返回值来resolve.</dd>
<dt><a href="Reference/Global_Objects/Promise/finally" title="返回一个设置了 finally 回调函数的Promise对象。"><code>Promise.prototype.finally(onFinally)</code></a></dt>
<dd>添加一个事件处理回调于当前promise对象并且在原promise对象解析完毕后返回一个新的promise对象。回调会在当前promise运行完毕后被调用无论当前promise的状态是完成(fulfilled)还是失败(rejected)</dd>
</dl><p></p>
<h2 id="创建Promise">创建Promise</h2>
<p><code>Promise</code> 对象是由关键字 <code>new</code> 及其构造函数来创建的。该构造函数会把一个叫做“处理器函数”executor function的函数作为它的参数。这个“处理器函数”接受两个函数——<code>resolve</code> 和 <code>reject</code> ——作为其参数。当异步任务顺利完成且返回结果值时,会调用 <code>resolve</code> 函数;而当异步任务失败且返回失败原因(通常是一个错误对象)时,会调用<code>reject</code> 函数。</p>
<pre><code class="language-javascript">const myFirstPromise = new Promise((resolve, reject) =&gt; {
// ?做一些异步操作,最终会调用下面两者之一:
//
// resolve(someValue); // fulfilled
// ?或
// reject("failure reason"); // rejected
});</code></pre>
<p>想要某个函数?拥有promise功能只需让其返回一个promise即可。</p>
<pre><code class="language-javascript">function myAsyncFunction(url) {
return new Promise((resolve, reject) =&gt; {
const xhr = new XMLHttpRequest();
xhr.open("GET", url);
xhr.onload = () =&gt; resolve(xhr.responseText);
xhr.onerror = () =&gt; reject(xhr.statusText);
xhr.send();
});
};</code></pre>
<h2 id="示例">示例</h2>
<h3 id="非常简单的例子">非常简单的例子</h3>
<pre><code class="language-javascript">let myFirstPromise = new Promise(function(resolve, reject){
  //当异步代码执行成功时我们才会调用resolve(...), 当异步代码失败时就会调用reject(...)
  //在本例中我们使用setTimeout(...)来模拟异步代码实际编码时可能是XHR请求或是HTML5的一些API方法.
setTimeout(function(){
  resolve("成功!"); //代码正常执行!
  }, 250);
});
myFirstPromise.then(function(successMessage){
  //successMessage的值是上面调用resolve(...)方法传入的值.
  //successMessage参数不一定非要是字符串类型这里只是举个例子
  console.log("Yay! " + successMessage);
});
</code></pre>
<h3 id="高级一点的例子">高级一点的例子</h3>
<pre><code class="language-html hidden">&lt;button id="btn"&gt;Make a promise!&lt;/button&gt;
&lt;div id="log"&gt;&lt;/div&gt;
</code></pre>
<p>本例展示了 <code>Promise</code> 的一些机制。 <code>testPromise()</code> 方法在每次点击 <a href="/zh-CN/docs/Web/HTML/Element/button" title="HTML &lt;button&gt; 元素表示一个可点击的按钮,可以用在表单或文档其它需要使用简单标准按钮的地方。"><code>&lt;button&gt;</code></a> 按钮时被调用该方法会创建一个promise 对象,使用 <a href="/zh-CN/docs/Web/API/Window/setTimeout" title="WindowOrWorkerGlobalScope 混合的 setTimeout()方法设置一个定时器,该定时器在定时器到期后执行一个函数或指定的一段代码。"><code>window.setTimeout()</code></a> 让Promise等待 1-3 秒不等的时间来填充数据通过Math.random()方法)。</p>
<p>Promise 的值的填充过程都被日志记录logged下来这些日志信息展示了方法中的同步代码和异步代码是如何通过Promise完成解耦的。</p>
<pre><code class="language-javascript">'use strict';
var promiseCount = 0;
function testPromise() {
let thisPromiseCount = ++promiseCount;
let log = document.getElementById('log');
log.insertAdjacentHTML('beforeend', thisPromiseCount +
') 开始 (&lt;small&gt;同步代码开始&lt;/small&gt;)&lt;br/&gt;');
  // 新构建一个 Promise 实例使用Promise实现每过一段时间给计数器加一的过程每段时间间隔为1~3秒不等
let p1 = new Promise(
// resolver 函数在 Promise 成功或失败时都可能被调用
(resolve, reject) =&gt; {
log.insertAdjacentHTML('beforeend', thisPromiseCount +
') Promise 开始 (&lt;small&gt;异步代码开始&lt;/small&gt;)&lt;br/&gt;');
// 创建一个异步调用
window.setTimeout(
function() {
// 填充 Promise
resolve(thisPromiseCount);
}, Math.random() * 2000 + 1000);
}
);
// Promise 不论成功或失败都会调用 then
// catch() 只有当 promise 失败时才会调用
p1.then(
// 记录填充值
function(val) {
log.insertAdjacentHTML('beforeend', val +
') Promise 已填充完毕 (&lt;small&gt;异步代码结束&lt;/small&gt;)&lt;br/&gt;');
})
.catch(
// 记录失败原因
(reason) =&gt; {
console.log('处理失败的 promise ('+reason+')');
});
log.insertAdjacentHTML('beforeend', thisPromiseCount +
') Promise made (&lt;small&gt;同步代码结束&lt;/small&gt;)&lt;br/&gt;');
}</code></pre>
<pre><code class="language-js hidden">if ("Promise" in window) {
let btn = document.getElementById("btn");
btn.addEventListener("click",testPromise);
} else {
log = document.getElementById('log');
log.innerHTML = "Live example not available as your browser doesn't support the &lt;code&gt;Promise&lt;code&gt; interface.";
}
</code></pre>
<p>点击下面的按钮可以看到示例代码运行的效果,前提是你的浏览器支持 <code>Promise</code>。快速点击按钮多次你会观察到Promises填充值的过程。</p>
<p><iframe class="live-sample-frame sample-code-frame" frameborder="0" height="200" id="frame_高级一点的例子" src="https://mdn.mozillademos.orgReference/Global_Objects/Promise$samples/%E9%AB%98%E7%BA%A7%E4%B8%80%E7%82%B9%E7%9A%84%E4%BE%8B%E5%AD%90?revision=1535408" width="500"></iframe></p>
<h2 id="使用_XHR_加载图像">使用 XHR 加载图像</h2>
<p><font face="Open Sans, sans-serif">另一个用了 </font>Promise <font face="Open Sans, sans-serif"></font><a href="/en-US/docs/Web/API/XMLHttpRequest"> XMLHttpRequest</a> 加载一个图像的例子可在MDN GitHub<a class="external" href="https://github.com/mdn/js-examples/tree/master/promises-test" rel="noopener"> promise-test</a> 中找到。 你也可以<a class="external" href="https://mdn.github.io/js-examples/promises-test/" rel="noopener">看这个实例</a>。每一步都有注释可以让你详细的了解Promise和XHR架构。</p>
<h2 id="规范">规范</h2>
<table class="standard-table">
<tbody>
<tr>
<th scope="col">规范</th>
<th scope="col">状态</th>
<th scope="col">备注</th>
</tr>
<tr>
<td><a class="external" href="https://www.ecma-international.org/ecma-262/6.0/#sec-promise-objects" hreflang="en" lang="en" rel="noopener">ECMAScript 2015 (6th Edition, ECMA-262)<br/><small lang="zh-CN">Promise</small></a></td>
<td><span class="spec-Standard">Standard</span></td>
<td>ECMA标准中的首次定义</td>
</tr>
<tr>
<td><a class="external" href="https://tc39.github.io/ecma262/#sec-promise-objects" hreflang="en" lang="en" rel="noopener">ECMAScript Latest Draft (ECMA-262)<br/><small lang="zh-CN">Promise</small></a></td>
<td><span class="spec-Draft">Draft</span></td>
<td> </td>
</tr>
</tbody>
</table>
<h2 id="浏览器兼容性">浏览器兼容性</h2>
<p class="hidden">To contribute to this compatibility data, please write a pull request against this repository: <a class="external" href="https://github.com/mdn/browser-compat-data" rel="noopener">https://github.com/mdn/browser-compat-data</a>.</p>
<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>Promise</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>
32</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>
Yes</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>
29</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-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>
19</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>
8</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>
4.4.3</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>
32</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>
29</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>
8</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>
0.12</td></tr><tr><th scope="row"><code>Promise()</code> constructor</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>
32</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>
Yes</td><td class="bc-supports-yes bc-browser-firefox bc-has-history"><span class="bc-browser-name">Firefox</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
29<div class="bc-icons"><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> </div><section class="bc-history" id="sect1"><dl><dt class="bc-supports-yes bc-supports"><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
29<div class="bc-icons"><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> </div></dt><dd><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> Constructor requires a new operator since version 37.</dd></dl></section></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-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>
19</td><td class="bc-supports-yes bc-browser-safari bc-has-history"><span class="bc-browser-name">Safari</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
8<div class="bc-icons"><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> </div><section class="bc-history" id="sect2"><dl><dt class="bc-supports-yes bc-supports"><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
8<div class="bc-icons"><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> </div></dt><dd><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> Constructor requires a new operator since version 10.</dd></dl></section></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>
4.4.3</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>
32</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 bc-has-history"><span class="bc-browser-name">Firefox Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
29<div class="bc-icons"><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> </div><section class="bc-history" id="sect3"><dl><dt class="bc-supports-yes bc-supports"><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
29<div class="bc-icons"><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> </div></dt><dd><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> Constructor requires a new operator since version 37.</dd></dl></section></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 bc-has-history"><span class="bc-browser-name">Safari iOS</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
8<div class="bc-icons"><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> </div><section class="bc-history" id="sect4"><dl><dt class="bc-supports-yes bc-supports"><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
8<div class="bc-icons"><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> </div></dt><dd><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> Constructor requires a new operator since version 10.</dd></dl></section></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 bc-has-history"><span class="bc-browser-name">nodejs</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
0.12<div class="bc-icons"><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> </div><section class="bc-history" id="sect5"><dl><dt class="bc-supports-yes bc-supports"><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
0.12<div class="bc-icons"><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> </div></dt><dd><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> Constructor requires a new operator since version 4.</dd></dl></section></td></tr><tr><th scope="row"><a href="Reference/Global_Objects/Promise/all"><code>all</code></a></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>
32</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>
29</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-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>
19</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>
8</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>
4.4.3</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>
32</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>
29</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>
8</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>
0.12</td></tr><tr><th scope="row"><a href="Reference/Global_Objects/Promise/prototype"><code>prototype</code></a></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>
32</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>
Yes</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>
29</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-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>
19</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>
8</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>
4.4.3</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>
32</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>
29</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>
8</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>
0.12</td></tr><tr><th scope="row"><a href="Reference/Global_Objects/Promise/catch"><code>catch</code></a></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>
32</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>
29</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-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>
19</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>
8</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>
4.4.3</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>
32</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>
29</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>
8</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>
0.12</td></tr><tr><th scope="row"><a href="Reference/Global_Objects/Promise/finally"><code>finally</code></a></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>
63</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>
18</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>
58</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-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>
50</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>
11.1</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>
63</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>
63</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-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>
58</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>
46</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>
11.1</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-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>
10.0.0</td></tr><tr><th scope="row"><a href="Reference/Global_Objects/Promise/then"><code>then</code></a></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>
32</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>
29</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-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>
19</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>
8</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>
4.4.3</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>
32</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>
29</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>
8</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>
0.12</td></tr><tr><th scope="row"><a href="Reference/Global_Objects/Promise/race"><code>race</code></a></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>
32</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>
29</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-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>
19</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>
8</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>
4.4.3</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>
32</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>
29</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>
8</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>
0.12</td></tr><tr><th scope="row"><a href="Reference/Global_Objects/Promise/reject"><code>reject</code></a></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>
32</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>
29</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-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>
19</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>
8</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>
4.4.3</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>
32</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>
29</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>
8</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>
0.12</td></tr><tr><th scope="row"><a href="Reference/Global_Objects/Promise/resolve"><code>resolve</code></a></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>
32</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>
29</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-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>
19</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>
8</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>
4.4.3</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>
32</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>
29</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>
8</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>
0.12</td></tr></tbody></table><section class="bc-legend" id="sect6"><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><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="See implementation notes."><span>See implementation notes.</span><i class="ic-footnote"></i></abbr></dt><dd>See implementation notes.</dd></dl></section></div><p></p>
<h2 id="参见">参见</h2>
<ul>
<li><a class="external" href="http://promisesaplus.com/" rel="noopener">Promises/A+ specification</a></li>
<li><a class="external" href="https://medium.com/@ramsunvtech/promises-of-promise-part-1-53f769245a53" rel="noopener">Venkatraman.R - JS Promise (Part 1, Basics)</a></li>
<li><a class="external" href="https://medium.com/@ramsunvtech/js-promise-part-2-q-js-when-js-and-rsvp-js-af596232525c#.dzlqh6ski" rel="noopener">Venkatraman.R - JS Promise (Part 2 - Using Q.js, When.js and RSVP.js)</a></li>
<li><a class="external" href="http://www.html5rocks.com/en/tutorials/es6/promises/" rel="noopener">Jake Archibald: JavaScript Promises: There and Back Again</a></li>
<li><a class="external" href="http://de.slideshare.net/domenicdenicola/callbacks-promises-and-coroutines-oh-my-the-evolution-of-asynchronicity-in-javascript" rel="noopener">Domenic Denicola: Callbacks, Promises, and Coroutines Asynchronous Programming Patter in JavaScript</a></li>
<li><a class="external" href="http://www.mattgreer.org/articles/promises-in-wicked-detail/" rel="noopener">Matt Greer: JavaScript Promises ... In Wicked Detail</a></li>
<li><a class="external" href="https://www.promisejs.org/" rel="noopener">Forbes Lindesay: promisejs.org</a></li>
<li><a class="external" href="http://pouchdb.com/2015/05/18/we-have-a-problem-with-promises.html" rel="noopener">Nolan Lawson: We have a problem with promises — Common mistakes with promises</a></li>
<li><a class="external" href="https://github.com/jakearchibald/es6-promise/" rel="noopener">Promise polyfill</a></li>
<li><a class="external" href="https://www.udacity.com/course/javascript-promises--ud898" rel="noopener">Udacity: JavaScript Promises</a></li>
</ul>
</article>