uTools-Manuals/docs/javascript/Reference/Global_Objects/WebAssembly/instantiate.html

<article id="wikiArticle">
<div><div class="blockIndicator experimental indicator-warning">
<p><span title="这是一个实验性的 API，请尽量不要在生产环境中使用它。"><i class="icon-beaker"> </i></span> <strong>这是一个实验中的功能</strong><br/>此功能某些浏览器尚在开发中，请参考<a href="#Browser_compatibility">浏览器兼容性表格</a>以得到在不同浏览器中适合使用的前缀。由于该功能对应的标准文档可能被重新修订，所以在未来版本的浏览器中该功能的语法和行为可能随之改变。</p>
</div></div>
<p><strong><code>WebAssembly.instantiate()</code></strong> 是编译和实例化 WebAssembly 代码的主要方法.  这个方法有两个重载方式:</p>
<ul>
<li>第一种重载使用WebAssembly二进制代码的 <a href="/en-US/docs/Web/JavaScript/Typed_arrays">typed array</a> 或 <a href="/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer">ArrayBuffer</a> 形式进行编译和实例化.  返回的 <code>Promise</code> 会携带已编译的 <a href="Reference/Global_Objects/WebAssembly/Module" title="所有 Module 实例继承自 Module() 构造函数的原型对象 —— 修改它会影响所有 Module 实例。"><code>WebAssembly.Module</code></a> 和它的第一个实例化对象 <a href="Reference/Global_Objects/WebAssembly/Instance" title="一个 WebAssembly.Instance 对象是有状态的, 是WebAssembly.Module 的一个可执行实例.  实例包含所有的 WebAssembly 导出函数 ,允许从JavaScript 调用 WebAssembly 代码."><code>WebAssembly.Instance</code></a>.</li>
<li>第二种重载使用已编译的 <a href="Reference/Global_Objects/WebAssembly/Module" title="所有 Module 实例继承自 Module() 构造函数的原型对象 —— 修改它会影响所有 Module 实例。"><code>WebAssembly.Module</code></a> , 返回的 <code>Promise</code> 携带一个 <code>Module</code>的实例化对象 <code>Instance</code>. 如果这个 <code>Module</code> 已经被编译了或者是从缓存中获取的( <a href="/en-US/docs/WebAssembly/Caching_modules">retrieved from cache</a>), 那么这种重载方式是非常有用的.</li>
</ul>
<h2 id="语法">语法</h2>
<h3 id="主重载方式_—_使用wasm二进制代码">主重载方式 — 使用wasm二进制代码</h3>
<pre><code class="language-javascript">Promise&lt;ResultObject&gt; WebAssembly.instantiate(bufferSource, importObject);
</code></pre>
<h4 id="参数">参数</h4>
<dl>
<dt><em>bufferSource</em></dt>
<dd>一个包含你想编译的wasm模块二进制代码的 <a href="/en-US/docs/Web/JavaScript/Typed_arrays">typed array</a>(类型数组) or <a href="/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer">ArrayBuffer</a>(数组缓冲区)</dd>
<dt><em>importObject</em> <span class="inlineIndicator optional optionalInline">可选</span></dt>
<dd>一个将被导入到新创建实例中的对象，它包含的值有函数、<a href="Reference/Global_Objects/WebAssembly/Memory" title="WebAssembly.Memory() 构造函数创建一个新的 Memory 对象。它包含一个可调整大小的 ArrayBuffer ，其内存储的是 WebAssembly 实例 所访问内存的原始字节码。"><code>WebAssembly.Memory</code></a> 对象等等。编译的模块中，对于每一个导入的值都要有一个与其匹配的属性与之相对应，否则将会抛出 <a href="/en-US/docs/Web/JavaScript/Reference/Global_Objects/WebAssembly/LinkError">WebAssembly.LinkError</a>。</dd>
</dl>
<h4 id="返回值">返回值</h4>
<p>解析为包含两个字段的 <code>ResultObject</code> 的一个 <code>Promise</code>:</p>
<ul>
<li><code>module</code>: 一个被编译好的 <a href="Reference/Global_Objects/WebAssembly/Module" title="所有 Module 实例继承自 Module() 构造函数的原型对象 —— 修改它会影响所有 Module 实例。"><code>WebAssembly.Module</code></a> 对象. 这个模块可以被再次实例化，通过 <a href="/en-US/docs/Web/API/Worker/postMessage">postMessage()</a> 被分享，或者缓存到 <a href="/en-US/docs/WebAssembly/Caching_modules">IndexedDB</a>。</li>
<li><code>instance</code>: 一个包含所有 <a href="/en-US/docs/WebAssembly/Exported_functions">Exported WebAssembly functions</a>的<a href="Reference/Global_Objects/WebAssembly/Instance" title="一个 WebAssembly.Instance 对象是有状态的, 是WebAssembly.Module 的一个可执行实例.  实例包含所有的 WebAssembly 导出函数 ,允许从JavaScript 调用 WebAssembly 代码."><code>WebAssembly.Instance</code></a>对象。</li>
</ul>
<h4 id="异常">异常</h4>
<ul>
<li>如果参数的类型或结构不正确，将会抛出异常 <a href="Reference/Global_Objects/TypeError" title="TypeError（类型错误） 对象用来表示值的类型非预期类型时发生的错误。"><code>TypeError</code></a> .</li>
<li>如果操作失败，promise 将会被 reject 掉， 根据失败的原因不同，会抛出3种异常，<a class="new" href="Reference/Global_Objects/WebAssembly/CompileError" rel="nofollow" title="此页面仍未被本地化, 期待您的翻译!"><code>WebAssembly.CompileError</code></a>，<a href="Reference/Global_Objects/WebAssembly/LinkError" title="此页面仍未被本地化, 期待您的翻译!"><code>WebAssembly.LinkError</code></a>, 或<a class="new" href="Reference/Global_Objects/WebAssembly/RuntimeError" rel="nofollow" title="此页面仍未被本地化, 期待您的翻译!"><code>WebAssembly.RuntimeError</code></a>。</li>
</ul>
<h3 id="第二种重载_—_使用模块对象">第二种重载 — 使用模块对象</h3>
<pre><code class="language-javascript">Promise&lt;WebAssembly.Instance&gt; WebAssembly.instantiate(module, importObject);
</code></pre>
<h4 id="参数_2">参数</h4>
<dl>
<dt><em>module</em></dt>
<dd>将被实例化的 <a href="Reference/Global_Objects/WebAssembly/Module" title="所有 Module 实例继承自 Module() 构造函数的原型对象 —— 修改它会影响所有 Module 实例。"><code>WebAssembly.Module</code></a> 对象。</dd>
<dt><em>importObject</em> <span class="inlineIndicator optional optionalInline">可选</span></dt>
<dd>一个将被导入到新创建实例中的对象，它包含的值有函数、<a href="Reference/Global_Objects/WebAssembly/Memory" title="WebAssembly.Memory() 构造函数创建一个新的 Memory 对象。它包含一个可调整大小的 ArrayBuffer ，其内存储的是 WebAssembly 实例 所访问内存的原始字节码。"><code>WebAssembly.Memory</code></a> 对象等等。编译的模块中，对于每一个导入的值都要有一个与其匹配的属性与之相对应，否则将会抛出 <a href="/en-US/docs/Web/JavaScript/Reference/Global_Objects/WebAssembly/LinkError">WebAssembly.LinkError</a>。</dd>
</dl>
<h4 id="返回值_2">返回值</h4>
<p>一个解析为 <a href="Reference/Global_Objects/WebAssembly/Instance" title="一个 WebAssembly.Instance 对象是有状态的, 是WebAssembly.Module 的一个可执行实例.  实例包含所有的 WebAssembly 导出函数 ,允许从JavaScript 调用 WebAssembly 代码."><code>WebAssembly.Instance</code></a> 的<code>Promise</code> 对象。</p>
<h4 id="异常_2">异常</h4>
<ul>
<li>如果参数的类型或结构不正确，将抛出异常 <a href="Reference/Global_Objects/TypeError" title="TypeError（类型错误） 对象用来表示值的类型非预期类型时发生的错误。"><code>TypeError</code></a> 。</li>
<li>如果操作失败，promise 将会被 reject 掉， 根据失败的原因不同，会抛出3种异常，<a class="new" href="Reference/Global_Objects/WebAssembly/CompileError" rel="nofollow" title="此页面仍未被本地化, 期待您的翻译!"><code>WebAssembly.CompileError</code></a>，<a href="Reference/Global_Objects/WebAssembly/LinkError" title="此页面仍未被本地化, 期待您的翻译!"><code>WebAssembly.LinkError</code></a>, 或<a class="new" href="Reference/Global_Objects/WebAssembly/RuntimeError" rel="nofollow" title="此页面仍未被本地化, 期待您的翻译!"><code>WebAssembly.RuntimeError</code></a>。</li>
</ul>
<h2 id="例子">例子</h2>
<h3 id="第一种重载例子">第一种重载例子</h3>
<p>使用 fetch 获取一些 WebAssembly 二进制代码后，我们使用 <a href="Reference/Global_Objects/WebAssembly/instantiate" title="WebAssembly.instantiate() 是编译和实例化 WebAssembly 代码的主要方法.  这个方法有两个重载方式:"><code>WebAssembly.instantiate()</code></a>  方法编译并实例化模块，在此过程中，导入了一个 Javascript 方法在 WebAssembly 模块中， 接下来我们使用<code>Instance</code> 导出的<a href="/en-US/docs/WebAssembly/Exported_functions">Exported WebAssembly </a>方法。</p>
<pre><code  class="language-javascript">var importObject = {
  imports: {
    imported_func: function(arg) {
      console.log(arg);
    }
  }
};

fetch('simple.wasm').then(response =&gt;
  response.arrayBuffer()
).then(bytes =&gt;
  WebAssembly.instantiate(bytes, importObject)
).then(result =&gt;
  result.instance.exports.exported_func()
);</code></pre>
<div class="note">
<p><strong>注</strong>: 查看GitHub(<a class="external" href="https://mdn.github.io/webassembly-examples/js-api-examples/" rel="noopener">在线实例</a>)的 <a class="external" href="https://github.com/mdn/webassembly-examples/blob/master/js-api-examples/index.html" rel="noopener">index.html</a> 中一个相似的例子，使用了我们的<code><a class="external" href="https://github.com/mdn/webassembly-examples/blob/master/wasm-utils.js#L1" rel="noopener">fetchAndInstantiate()</a></code>库函数</p>
</div>
<h3 id="第二种重载例子">第二种重载例子</h3>
<p>下面的例子（查看我们GitHub的 <a class="external" href="https://github.com/mdn/webassembly-examples/blob/master/js-api-examples/index-compile.html" rel="noopener">index-compile.html</a> 例子，可在线演示）使用 <code>compile()</code> 方法编译了 simple.wasm 字节码，然后通过 <a href="/en-US/docs/Web/API/Worker/postMessage">postMessage()</a> 发送给一个线程 <a href="https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers_API">worker</a>。</p>
<pre><code  class="language-javascript">var worker = new Worker("wasm_worker.js");

fetch('simple.wasm').then(response =&gt;
  response.arrayBuffer()
).then(bytes =&gt;
  WebAssembly.compile(bytes)
).then(mod =&gt;
  worker.postMessage(mod)
);</code></pre>
<p>在线程中 (查看 <code><a class="external" href="https://github.com/mdn/webassembly-examples/blob/master/js-api-examples/wasm_worker.js" rel="noopener">wasm_worker.js</a></code>) 我们定义了一个导入对象供模块使用，然后设置了一个事件处理函数来接收主线程发来的模块。当模块被接收到后，我们使用<a href="Reference/Global_Objects/WebAssembly/instantiate" title="WebAssembly.instantiate() 是编译和实例化 WebAssembly 代码的主要方法.  这个方法有两个重载方式:"><code>WebAssembly.instantiate()</code></a> 方法创建一个实例并且调用它从内部导出的函数。</p>
<pre><code  class="language-javascript">var importObject = {
  imports: {
    imported_func: function(arg) {
      console.log(arg);
    }
  }
};

onmessage = function(e) {
  console.log('module received from main thread');
  var mod = e.data;

  WebAssembly.instantiate(mod, importObject).then(function(instance) {
    instance.exports.exported_func();
  });
};</code></pre>
<h2 id="Specifications">Specifications</h2>
<table class="standard-table">
<thead>
<tr>
<th scope="col">Specification</th>
<th scope="col">Status</th>
<th scope="col">Comment</th>
</tr>
</thead>
<tbody>
<tr>
<td><a class="external" href="https://webassembly.github.io/spec/js-api/#webassemblyinstantiate" hreflang="en" lang="en" rel="noopener">WebAssembly JavaScript Interface<br/><small lang="zh-CN">instantiate()</small></a></td>
<td><span class="spec-WD">Working Draft</span></td>
<td>Initial draft definition.</td>
</tr>
</tbody>
</table>
<h2 id="Browser_compatibility" name="Browser_compatibility">Browser compatibility</h2>
<div>
<div class="hidden">The compatibility table on 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>instantiate</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>
              57</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>
              16</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>
              52<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>
              52<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> Disabled in the Firefox 52 Extended Support Release (ESR).</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>
              44</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</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>
              57</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>
              57</td><td class="bc-supports-yes bc-browser-edge_mobile bc-has-history"><span class="bc-browser-name">Edge Mobile</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
              Yes<div class="bc-icons"><abbr class="only-icon" title="User must explicitly enable this feature."><span>Disabled</span><i class="ic-disabled"></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>
              Yes<div class="bc-icons"><abbr class="only-icon" title="User must explicitly enable this feature."><span>Disabled</span><i class="ic-disabled"></i></abbr> </div></dt><dd><abbr class="only-icon" title="User must explicitly enable this feature."><span>Disabled</span><i class="ic-disabled"></i></abbr> This feature is behind the <code>Experimental JavaScript Features</code> preference.</dd></dl></section></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>
              52<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>
              52<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> Disabled in the Firefox 52 Extended Support Release (ESR).</dd></dl></section></td><td class="bc-supports-unknown bc-browser-opera_android"><span class="bc-browser-name">Opera Android</span><abbr title="Compatibility unknown; please update this.">
                ?
              </abbr></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</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>
              7.0</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>
              8.0.0</td></tr></tbody></table><section class="bc-legend" id="sect4"><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><span class="bc-supports-unknown bc-supports">
<abbr class="bc-level bc-level-unknown only-icon" title="Compatibility unknown">
<span>Compatibility unknown</span>
                  
                </abbr></span></dt><dd>Compatibility unknown</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><dt><abbr class="only-icon" title="User must explicitly enable this feature."><span>User must explicitly enable this feature.</span><i class="ic-disabled"></i></abbr></dt><dd>User must explicitly enable this feature.</dd></dl></section></div><p></p>
</div>
<h2 id="See_also">See also</h2>
<ul>
<li><a href="/en-US/docs/WebAssembly">WebAssembly</a> overview page</li>
<li><a href="/en-US/docs/WebAssembly/Concepts">WebAssembly concepts</a></li>
<li><a href="/en-US/docs/WebAssembly/Using_the_JavaScript_API">Using the WebAssembly JavaScript API</a></li>
</ul>
</article>