在此页

• 构造函数
• 特性
• 方法
• 范例
• 规范
• 浏览器兼容性
• 相关话题

ReadableStreamDefaultReader 接口在 Streams API represents a default reader that can be used to read stream data supplied from a network (e.g. a fetch request).

构造函数

ReadableStreamDefaultReader()

创建并返回 ReadableStreamDefaultReader 对象实例。

特性

ReadableStreamDefaultReader.closed 只读

Allows you to write code that responds to an end to the streaming process. Returns a promise that fulfills if the stream becomes closed or the reader's lock is released, or rejects if the stream errors.

方法

ReadableStreamDefaultReader.cancel()

Cancels the stream, signaling a loss of interest in the stream by a consumer. The supplied reason argument will be given to the underlying source, which may or may not use it.

ReadableStreamDefaultReader.read()

Returns a promise providing access to the next chunk in the stream's internal queue.

ReadableStreamDefaultReader.releaseLock()

Releases the reader's lock on the stream.

范例

In the following example, an artifical 响应 is created to stream HTML fragments fetched from another resource to the browser.

It demonstrates the usage of a ReadableStream in combination with a Uint8Array .

fetch("https://www.example.org/").then((response) => {
  const reader = response.body.getReader();
  const stream = new ReadableStream({
    start(controller) {
      // The following function handles each data chunk
      function push() {
        // "done" is a Boolean and value a "Uint8Array"
        return reader.read().then(({ done, value }) => {
          // Is there no more data to read?
          if (done) {
            // Tell the browser that we have finished sending data
            controller.close();
            return;
          }
          // Get the data and send it to the browser via the controller
          controller.enqueue(value);
          push();
        });
      };
      push();
    }
  });
  return new Response(stream, { headers: { "Content-Type": "text/html" } });
});
					

规范

规范	状态	注释
流 The definition of 'ReadableStreamDefaultReader' in that specification.	实时标准	初始定义

浏览器兼容性

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request. 更新 GitHub 上的兼容性数据

	桌面						移动
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
ReadableStreamDefaultReader	Chrome 52	Edge ≤79	Firefox 65 65 57 Disabled Disabled From version 57: this feature is behind the dom.streams.enabled preference (needs to be set to true ) 和 preference (needs to be set to ). To change preferences in Firefox, visit about:config.	IE ?	Opera 39	Safari ?	WebView Android 52	Chrome Android 52	Firefox Android 65 65 57 Disabled Disabled From version 57: this feature is behind the dom.streams.enabled preference (needs to be set to true ) 和 preference (needs to be set to ). To change preferences in Firefox, visit about:config.	Opera Android 41	Safari iOS ?	Samsung Internet Android 6.0
ReadableStreamDefaultReader() 构造函数	Chrome ?	Edge ?	Firefox 65 65 57 Disabled Disabled From version 57: this feature is behind the dom.streams.enabled preference (needs to be set to true ) 和 preference (needs to be set to ). To change preferences in Firefox, visit about:config.	IE ?	Opera ?	Safari ?	WebView Android ?	Chrome Android ?	Firefox Android 65 65 57 Disabled Disabled From version 57: this feature is behind the dom.streams.enabled preference (needs to be set to true ) 和 preference (needs to be set to ). To change preferences in Firefox, visit about:config.	Opera Android ?	Safari iOS ?	Samsung Internet Android ?
cancel	Chrome ?	Edge ?	Firefox 65 65 57 Disabled Disabled From version 57: this feature is behind the dom.streams.enabled preference (needs to be set to true ) 和 preference (needs to be set to ). To change preferences in Firefox, visit about:config.	IE ?	Opera ?	Safari ?	WebView Android ?	Chrome Android ?	Firefox Android 65 65 57 Disabled Disabled From version 57: this feature is behind the dom.streams.enabled preference (needs to be set to true ) 和 preference (needs to be set to ). To change preferences in Firefox, visit about:config.	Opera Android ?	Safari iOS ?	Samsung Internet Android ?
closed	Chrome ?	Edge ?	Firefox 65 65 57 Disabled Disabled From version 57: this feature is behind the dom.streams.enabled preference (needs to be set to true ) 和 preference (needs to be set to ). To change preferences in Firefox, visit about:config.	IE ?	Opera ?	Safari ?	WebView Android ?	Chrome Android ?	Firefox Android 65 65 57 Disabled Disabled From version 57: this feature is behind the dom.streams.enabled preference (needs to be set to true ) 和 preference (needs to be set to ). To change preferences in Firefox, visit about:config.	Opera Android ?	Safari iOS ?	Samsung Internet Android ?
read	Chrome ?	Edge ?	Firefox 65 65 57 Disabled Disabled From version 57: this feature is behind the dom.streams.enabled preference (needs to be set to true ) 和 preference (needs to be set to ). To change preferences in Firefox, visit about:config.	IE ?	Opera ?	Safari ?	WebView Android ?	Chrome Android ?	Firefox Android 65 65 57 Disabled Disabled From version 57: this feature is behind the dom.streams.enabled preference (needs to be set to true ) 和 preference (needs to be set to ). To change preferences in Firefox, visit about:config.	Opera Android ?	Safari iOS ?	Samsung Internet Android ?
releaseLock	Chrome ?	Edge ?	Firefox 65 65 57 Disabled Disabled From version 57: this feature is behind the dom.streams.enabled preference (needs to be set to true ) 和 preference (needs to be set to ). To change preferences in Firefox, visit about:config.	IE ?	Opera ?	Safari ?	WebView Android ?	Chrome Android ?	Firefox Android 65 65 57 Disabled Disabled From version 57: this feature is behind the dom.streams.enabled preference (needs to be set to true ) 和 preference (needs to be set to ). To change preferences in Firefox, visit about:config.	Opera Android ?	Safari iOS ?	Samsung Internet Android ?

图例

完整支持

完整支持

兼容性未知 ?

兼容性未知

实验。期望将来行为有所改变。

实验。期望将来行为有所改变。

用户必须明确启用此特征。

用户必须明确启用此特征。

元数据

• 最后修改： Jan 17, 2020

相关话题

1. Streams API
2. ReadableStreamDefaultReader
3. 构造函数

   1. ReadableStreamDefaultReader()
4. 特性

   1. closed
5. 方法

   1. cancel()
   2. read()
   3. releaseLock()
6. Related pages for Streams

   1. Body.body
   2. ByteLengthQueuingStrategy
   3. CountQueuingStrategy
   4. ReadableByteStreamController
   5. ReadableStream
   6. ReadableStreamBYOBReader
   7. ReadableStreamBYOBRequest
   8. ReadableStreamDefaultController
   9. WindowOrWorkerGlobalScope.fetch()
   10. WritableStream
   11. WritableStreamDefaultController
   12. WritableStreamDefaultWriter