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

<p><strong><code>BigInt.asUintN</code></strong> 静态方法将 <code>BigInt</code> 转换为一个 0 和 2^width-1 之间的无符号整数。</p>

<div>{{EmbedInteractiveExample("pages/js/bigint-asuintn.html")}}</div>



<h2 id="语法">语法</h2>

<pre class="syntaxbox">BigInt.asUintN(<var>width</var>, <var>bigint</var>);</pre>

<h3 id="参数">参数</h3>

<dl>
 <dt><code>width</code></dt>
 <dd>可存储整数的位数。</dd>
 <dt><code>bigint</code></dt>
 <dd> 要存储在指定位数上的整数。</dd>
</dl>

<h3 id="返回值">返回值</h3>

<p><code>bigint</code> 模(modulo) <code>2^width</code> 作为无符号整数的值。</p>

<h2 id="例子">例子</h2>

<h3 id="保持在64位范围内">保持在64位范围内</h3>

<p><code>BigInt.asUintN()</code> 方法对于保持在64位(64-bit)算数范围内非常有用。</p>

<pre class="brush: js">const max = 2n ** 64n - 1n;

BigInt.asUintN(64, max);
// ↪ 18446744073709551615n

BigInt.asUintN(64, max + 1n);
// ↪ 0n
// zero because of overflow</pre>

<h2 id="标准">标准</h2>

<table class="standard-table">
 <tbody>
  <tr>
   <th scope="col">Specification</th>
   <th scope="col">Status</th>
  </tr>
  <tr>
   <td>{{SpecName('ESDraft', '#sec-bigint.asuintn', 'BigInt.asUintN()')}}</td>
   <td>{{Spec2('ESDraft')}}</td>
  </tr>
 </tbody>
</table>

<h2 id="浏览器支持">浏览器支持</h2>



<p>{{Compat("javascript.builtins.BigInt.asUintN")}}</p>

<h2 id="请参阅">请参阅</h2>

<ul>
 <li>{{JSxRef("BigInt")}}</li>
 <li>{{JSxRef("BigInt.asIntN()")}}</li>
</ul>