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authorPeter Bengtsson <mail@peterbe.com>2020-12-08 14:40:17 -0500
committerPeter Bengtsson <mail@peterbe.com>2020-12-08 14:40:17 -0500
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+---
+title: ReadableStream.getReader()
+slug: Web/API/ReadableStream/getReader
+tags:
+ - API
+ - getReader
+ - 参考
+ - 可读取流
+ - 方法
+ - 流
+translation_of: Web/API/ReadableStream/getReader
+---
+<div>{{APIRef("Streams")}}</div>
+
+<p class="summary">使用{{domxref("ReadableStream")}}接口的<strong><code>getReader()</code></strong> 方法创建一个<code>reader</code>,并将流锁定。只有当前<code>reader</code>将流释放后,其他<code>reader</code>才能使用。</p>
+
+<h2 id="语法">语法</h2>
+
+<pre class="syntaxbox notranslate">var reader = readableStreamInstance.getReader(<em>{mode}</em>);</pre>
+
+<h3 id="参数">参数</h3>
+
+<dl>
+ <dt>{mode}- 可选参数</dt>
+ <dd>具有 <code>mode</code>参数的对象,值为  {{domxref("DOMString")}}类型 ,用来指定要创建的阅读器的类型。其值可以是:
+ <ul>
+ <li><code>byob</code>, 结果为 {{domxref("ReadableStreamBYOBReader")}} 类型,可读取可读字节流。</li>
+ <li><code>undefined</code> (未定类型 — 默认值), 返回{{domxref("ReadableStreamDefaultReader")}} ,可以从流中返回单个块。</li>
+ </ul>
+ </dd>
+</dl>
+
+<h3 id="返回值">返回值</h3>
+
+<p>{{domxref("ReadableStreamDefaultReader")}} 类型或{{domxref("ReadableStreamBYOBReader")}} 类型 实例, 取决于 <code>mode</code> 值.</p>
+
+<h3 id="错误">错误</h3>
+
+<dl>
+ <dt>RangeError——范围错误</dt>
+ <dd>提供的 mode值 既不是 <font face="consolas, Liberation Mono, courier, monospace"><span style="background-color: rgba(220, 220, 220, 0.5);">byob</span></font>也不是  <font face="consolas, Liberation Mono, courier, monospace"><span style="background-color: rgba(220, 220, 220, 0.5);">undefined</span></font></dd>
+ <dt>TypeError——类型错误</dt>
+ <dd>尝试创建阅读器的流不是 {{domxref("ReadableStream")}}类型</dd>
+</dl>
+
+<h2 id="例子">例子</h2>
+
+<p>下面是个简单的例子, 在读取<code>ReadableStream</code>前,使用 <code>getReader()</code>创建一个{{domxref("ReadableStreamDefaultReader")}} 。(查看全部代码 <a href="https://mdn.github.io/dom-examples/streams/simple-random-stream/">Simple random stream example</a> ). 按顺序读取每个块,并传递给UI, 当整个流被读取完毕后, 从递归方法中退出,并在UI的另一部分输出整个流。</p>
+
+<pre class="brush: js notranslate">function fetchStream() {
+ const reader = stream.getReader();
+ let charsReceived = 0;
+
+ // read() 返回了一个promise
+ // 当数据被接收时resolve
+ reader.read().then(function processText({ done, value }) {
+ // Result对象包含了两个属性:
+ // done - 当stream传完所有数据时则变成true
+ // value - 数据片段。当done不为true时永远为undefined
+ if (done) {
+ console.log("Stream complete");
+ para.textContent = value;
+ return;
+ }
+
+ // value for fetch streams is a Uint8Array
+ charsReceived += value.length;
+ const chunk = value;
+ let listItem = document.createElement('li');
+ listItem.textContent = 'Received ' + charsReceived + ' characters so far. Current chunk = ' + chunk;
+ list2.appendChild(listItem);
+
+ result += chunk;
+
+ // 再次调用这个函数以读取更多数据
+ return reader.read().then(processText);
+ });
+}</pre>
+
+<h2 id="说明">说明</h2>
+
+<table class="standard-table">
+ <tbody>
+ <tr>
+ <th scope="col">Specification</th>
+ <th scope="col">Status(状态)</th>
+ <th scope="col">Comment(备注)</th>
+ </tr>
+ <tr>
+ <td>{{SpecName("Streams","#rs-get-reader","getReader()")}}</td>
+ <td>{{Spec2('Streams')}}</td>
+ <td>Initial definition.</td>
+ </tr>
+ </tbody>
+</table>
+
+<h2 id="浏览器兼容">浏览器兼容</h2>
+
+<div class="hidden">
+<p>The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out <a href="https://github.com/mdn/browser-compat-data">https://github.com/mdn/browser-compat-data</a> and send us a pull request.</p>
+</div>
+
+<p>{{Compat("api.ReadableStream.getReader")}}</p>