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

ReadableStreamDefaultController 接口在 Streams API represents a controller allowing control of a ReadableStream 's state and internal queue. Default controllers are for streams that are not byte streams.

构造函数

None. ReadableStreamDefaultController instances are created automatically during ReadableStream construction.

特性

ReadableStreamDefaultController.desiredSize 只读

Returns the desired size required to fill the stream's internal queue.

方法

ReadableStreamDefaultController.close()

Closes the associated stream.

ReadableStreamDefaultController.enqueue()

Enqueues a given chunk in the associated stream.

ReadableStreamDefaultController.error()

Causes any future interactions with the associated stream to error.

范例

In the following simple example, a custom ReadableStream is created using a constructor (see our Simple random stream example for the full code). The start() function generates a random string of text every second and enqueues it into the stream. A cancel() function is also provided to stop the generation if ReadableStream.cancel() is called for any reason.

注意， ReadableStreamDefaultController object is provided as the parameter of the start() and pull() 函数。

When a button is pressed, the generation is stopped, the stream is closed using ReadableStreamDefaultController.close() , and another function is run, which reads the data back out of the stream.

const stream = new ReadableStream({
  start(controller) {
    interval = setInterval(() => {
      let string = randomChars();
      // Add the string to the stream
      controller.enqueue(string);
      // show it on the screen
      let listItem = document.createElement('li');
      listItem.textContent = string;
      list1.appendChild(listItem);
    }, 1000);
    button.addEventListener('click', function() {
      clearInterval(interval);
      fetchStream();
      controller.close();
    })
  },
  pull(controller) {
    // We don't really need a pull in this example
  },
  cancel() {
    // This is called if the reader cancels,
    // so we should stop generating strings
    clearInterval(interval);
  }
});
					

规范

规范	状态	注释
流 The definition of 'ReadableStreamDefaultController' 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
ReadableStreamDefaultController	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
close	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 ?
desiredSize	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 ?
enqueue	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 ?
error	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： Feb 26, 2020

相关话题

1. Streams API
2. ReadableStreamDefaultController
3. 特性

   1. desiredSize
4. 方法

   1. close()
   2. enqueue()
   3. error()
5. Related pages for Streams

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