---
title: Promise.reject()
slug: Web/JavaScript/Reference/Global_Objects/Promise/reject
translation_of: Web/JavaScript/Reference/Global_Objects/Promise/reject
---
<div>{{JSRef}}</div>

<p><code><strong>Promise.reject(reason)</strong></code><strong> </strong>方法回傳一個以 <code>reason</code> 拒絕的 <code>Promise</code> 物件。</p>

<h2 id="語法">語法</h2>

<pre class="syntaxbox"><var>Promise.reject(reason)</var>;</pre>

<h3 id="參數">參數</h3>

<dl>
 <dt>reason</dt>
 <dd><code>Promise</code> 的失敗訊息。</dd>
</dl>

<h3 id="回傳值">回傳值</h3>

<p>一個以 <code>reason</code> 拒絕的 {{jsxref("Promise")}}。</p>

<h2 id="描述">描述</h2>

<p>靜態函式 <code>Promise.reject</code> 回傳一個被拒絕的 <code>Promise。由於除錯目的及選擇性錯誤捕捉（selective error catching），使</code>用一個 <code>instanceof</code> {{jsxref("Error")}} 作為 reason 是很有幫助的。</p>

<h2 id="範例">範例</h2>

<h3 id="使用靜態方法_Promise.reject()">使用靜態方法 Promise.reject()</h3>

<pre class="brush: js">Promise.reject(new Error('fail')).then(function(error) {
  // not called
}, function(error) {
  console.log(error); // Stacktrace
});</pre>

<h2 id="Specifications">Specifications</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.reject', 'Promise.reject')}}</td>
   <td>{{Spec2('ES2015')}}</td>
   <td>Initial definition in an ECMA standard.</td>
  </tr>
  <tr>
   <td>{{SpecName('ESDraft', '#sec-promise.reject', 'Promise.reject')}}</td>
   <td>{{Spec2('ESDraft')}}</td>
   <td> </td>
  </tr>
 </tbody>
</table>

<h2 id="Browser_compatibility">Browser compatibility</h2>

<p>{{Compat("javascript.builtins.Promise.reject")}}</p>

<h2 id="See_also">See also</h2>

<ul>
 <li>{{jsxref("Promise")}}</li>
 <li><a href="https://github.com/petkaantonov/bluebird#error-handling">Selective error catching using the BlueBird Promise library</a></li>
</ul>