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+---
+title: Promise.all()
+slug: Web/JavaScript/Reference/Global_Objects/Promise/all
+translation_of: Web/JavaScript/Reference/Global_Objects/Promise/all
+---
+<div>{{JSRef}}</div>
+
+<p><code><strong>Promise.all()</strong></code> 方法回傳一個 {{jsxref("Promise")}} 物件,當引數 <code>iterable</code> 中所有的 promises 都被實現(resolved),或引數 iterable 不含任何 promise 時,被實現。或以第一個被拒絕的 promise 的原因被拒絕。</p>
+
+<h2 id="語法">語法</h2>
+
+<pre class="syntaxbox"><var>Promise.all(iterable)</var>;</pre>
+
+<dl>
+ <dt>iterable</dt>
+ <dd>一個 <a href="https://developer.mozilla.org/zh-TW/docs/Web/JavaScript/Reference/Iteration_protocols#The_iterable_protocol">iterable</a> 物件像是 {{jsxref("Array")}} 或 {{jsxref("String")}}。</dd>
+</dl>
+
+<h3 id="回傳值">回傳值</h3>
+
+<ul>
+ <li>一個<strong>已被實現(already resolved)</strong>的 {{jsxref("Promise")}},若傳入的 iterable 為空。</li>
+ <li>一個<strong>非同步地被實現(asynchronously resolved)</strong>的 {{jsxref("Promise")}} 若傳入的 iterable 不含 promise。注意,Google Chrome 58 對此情形回傳一個<strong>已被解決</strong>的 promise。</li>
+ <li>一個<strong>擱置(pending)</strong>的 {{jsxref("Promise")}},對所有剩餘情形。此 promise 接著被<strong>非同步地</strong>被 resolved/rejected(只要堆疊為空)當 iterable 中所有的 promises 都被實現,或其中一個被拒絕。參見下方關於"Promise.all 的非同步與同步性質"的例子。</li>
+</ul>
+
+<h2 id="描述">描述</h2>
+
+<p>此方法在聚集(aggregating)多個 promises 的結果時很有幫助。</p>
+
+<p>實現(Fulfillment):<br>
+ 若傳入空的 iterable,此方法(同步地)回傳一個已被解決的 promise。若所有傳入的 promises 都被實現,或都不是 promise,<code>Promise.all</code> 回傳的 promise 被非同步地實現。無論是哪個情形,回傳一個以 iterable 其內<strong>所有</strong>值(包含非 promise 值)作為引數的陣列被實現。<br>
+  </p>
+
+<p>拒絕(Rejection):<br>
+ 若任一個傳入的 promise 被拒絕,Promise.all 非同步地以其值被拒絕,無論其他 promises 是否被解決。</p>
+
+<h2 id="範例">範例</h2>
+
+<h3 id="使用_Promise.all">使用 <code>Promise.all</code></h3>
+
+<p><code>Promise.all</code> 等到全部實現(或一個拒絕)。</p>
+
+<pre class="brush: js">var p1 = Promise.resolve(3);
+var p2 = 1337;
+var p3 = new Promise((resolve, reject) =&gt; {
+ setTimeout(resolve, 100, 'foo');
+});
+
+Promise.all([p1, p2, p3]).then(values =&gt; {
+ console.log(values); // [3, 1337, "foo"]
+});</pre>
+
+<p>若 iterable 含非 promise 值,它們將被忽略,但依然會被記入回傳 promise 陣列值(若被實現):</p>
+
+<pre class="brush: js">// this will be counted as if the iterable passed is empty, so it gets fulfilled
+var p = Promise.all([1,2,3]);
+// this will be counted as if the iterable passed contains only the resolved promise with value "444", so it gets fulfilled
+var p2 = Promise.all([1,2,3, Promise.resolve(444)]);
+// this will be counted as if the iterable passed contains only the rejected promise with value "555", so it gets rejected
+var p3 = Promise.all([1,2,3, Promise.reject(555)]);
+
+// using setTimeout we can execute code after the stack is empty
+setTimeout(function(){
+ console.log(p);
+ console.log(p2);
+ console.log(p3);
+});
+
+// logs
+// Promise { &lt;state&gt;: "fulfilled", &lt;value&gt;: Array[3] }
+// Promise { &lt;state&gt;: "fulfilled", &lt;value&gt;: Array[4] }
+// Promise { &lt;state&gt;: "rejected", &lt;reason&gt;: 555 }</pre>
+
+<h3 id="Promise.all_的非同步與同步性質"><code>Promise.all</code> 的非同步與同步性質</h3>
+
+<p>以下例子驗證了 <code>Promise.all</code> 的非同步性質(asynchronicity)(或同步性質(synchronicity),若傳入的 iterable 是空的):</p>
+
+<pre class="brush: js">// we are passing as argument an array of promises that are already resolved,
+// to trigger Promise.all as soon as possible
+var resolvedPromisesArray = [Promise.resolve(33), Promise.resolve(44)];
+
+var p = Promise.all(resolvedPromisesArray);
+// immediately logging the value of p
+console.log(p);
+
+// using setTimeout we can execute code after the stack is empty
+setTimeout(function(){
+ console.log('the stack is now empty');
+ console.log(p);
+});
+
+// logs, in order:
+// Promise { &lt;state&gt;: "pending" }
+// the stack is now empty
+// Promise { &lt;state&gt;: "fulfilled", &lt;value&gt;: Array[2] }
+</pre>
+
+<p><code>當</code> <code>Promise.all</code> 被拒絕時發生一樣的事情:</p>
+
+<pre class="brush: js">var mixedPromisesArray = [Promise.resolve(33), Promise.reject(44)];
+var p = Promise.all(mixedPromisesArray);
+console.log(p);
+setTimeout(function(){
+ console.log('the stack is now empty');
+ console.log(p);
+});
+
+// logs
+// Promise { &lt;state&gt;: "pending" }
+// the stack is now empty
+// Promise { &lt;state&gt;: "rejected", &lt;reason&gt;: 44 }
+</pre>
+
+<p>注意!<code>Promise.all</code> 同步地被解決<strong>若且唯若</strong>傳入的 iterable 為空:</p>
+
+<pre class="brush: js">var p = Promise.all([]); // will be immediately resolved
+var p2 = Promise.all([1337, "hi"]); // non-promise values will be ignored, but the evaluation will be done asynchronously
+console.log(p);
+console.log(p2)
+setTimeout(function(){
+ console.log('the stack is now empty');
+ console.log(p2);
+});
+
+// logs
+// Promise { &lt;state&gt;: "fulfilled", &lt;value&gt;: Array[0] }
+// Promise { &lt;state&gt;: "pending" }
+// the stack is now empty
+// Promise { &lt;state&gt;: "fulfilled", &lt;value&gt;: Array[2] }
+</pre>
+
+<h3 id="Promise.all_的失敗優先(fail-fast)行為"><code>Promise.all</code> 的失敗優先(fail-fast)行為</h3>
+
+<p><code>當任一個陣列成員被拒絕則</code> <code>Promise.all</code> 被拒絕。例如,若傳入四個將在一段時間後被解決的 promises,而其中一個立刻被拒絕,則 <code>Promise.all</code> 將立刻被拒絕。</p>
+
+<pre class="brush: js">var p1 = new Promise((resolve, reject) =&gt; {
+ setTimeout(resolve, 1000, 'one');
+});
+var p2 = new Promise((resolve, reject) =&gt; {
+ setTimeout(resolve, 2000, 'two');
+});
+var p3 = new Promise((resolve, reject) =&gt; {
+ setTimeout(resolve, 3000, 'three');
+});
+var p4 = new Promise((resolve, reject) =&gt; {
+ setTimeout(resolve, 4000, 'four');
+});
+var p5 = new Promise((resolve, reject) =&gt; {
+ reject('reject');
+});
+
+Promise.all([p1, p2, p3, p4, p5]).then(values =&gt; {
+ console.log(values);
+}, reason =&gt; {
+ console.log(reason)
+});
+
+//From console:
+//"reject"
+
+//You can also use .catch
+Promise.all([p1, p2, p3, p4, p5]).then(values =&gt; {
+ console.log(values);
+}).catch(reason =&gt; {
+ console.log(reason)
+});
+
+//From console:
+//"reject"
+
+</pre>
+
+<h2 id="規範">規範</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>{{SpecName('ES2015', '#sec-promise.all', 'Promise.all')}}</td>
+ <td>{{Spec2('ES2015')}}</td>
+ <td>Initial definition in an ECMA standard.</td>
+ </tr>
+ <tr>
+ <td>{{SpecName('ESDraft', '#sec-promise.all', 'Promise.all')}}</td>
+ <td>{{Spec2('ESDraft')}}</td>
+ <td> </td>
+ </tr>
+ </tbody>
+</table>
+
+<h2 id="瀏覽器相容性">瀏覽器相容性</h2>
+
+<p class="hidden">To contribute to this compatibility data, please write a pull request against this repository: <a href="https://github.com/mdn/browser-compat-data">https://github.com/mdn/browser-compat-data</a>.</p>
+
+<p>{{Compat("javascript.builtins.Promise.all")}}</p>
+
+<h2 id="參見">參見</h2>
+
+<ul>
+ <li>{{jsxref("Promise")}}</li>
+ <li>{{jsxref("Promise.race()")}}</li>
+</ul>