在此页

• 句法
• 范例
• 规范
• 浏览器兼容性
• 相关话题

这是 实验性技术
检查 浏览器兼容性表格 要小心谨慎在生产中使用这之前。

ready 只读特性在 WritableStreamDefaultWriter interface returns a Promise that resolves when the desired size of the stream's internal queue transitions from non-positive to positive, signaling that it is no longer applying backpressure.

句法

var promise = writableStreamDefaultWriter.ready;
					

值

A Promise .

范例

The following example shows two uses of the ready property. The first uses ready 以确保 WritableStream is done writing and thus able to receive data before sending a binary chunk. The second also checks whether the the WritableStream is done writing, but this time because the writing must be finished before the writer can be closed.

function sendMessage(message, writableStream) {
  // defaultWriter is of type WritableStreamDefaultWriter
  var defaultWriter = writableStream.getWriter();
  var encoder = new TextEncoder();
  var encoded = encoder.encode(message, {stream: true});
  encoded.forEach(function(chunk) {
    // Make sure the stream and its writer are able to
    //   receive data.
    defaultWriter.ready
    .then(function() {
      defaultWriter.write(chunk)
      .then(function() {
        console.log("Chunk written to sink.);
      })
      .catch(function(err) {
        console.log("Chunk error: " + err);
      });
    });
    // Call ready again to ensure that all chunks are written
    //   before closing the writer.
    defaultWriter.ready
    .then(function() {
      defaultWriter.close()
      .then(function() {
        console.log("All chunks written");
      })
      .catch(function(err) {
        console.log("Stream error: " + err);
      });
    });
  });
}
					

规范

规范	状态	注释
流 The definition of 'ready' 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
ready	Chrome 59	Edge 16	Firefox No	IE No	Opera 46	Safari ?	WebView Android 59	Chrome Android 59	Firefox Android No	Opera Android 43	Safari iOS ?	Samsung Internet Android 7.0

图例

完整支持

完整支持

不支持

不支持

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。

元数据

• 最后修改： Feb 16, 2020

相关话题

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

   1. WritableStreamDefaultWriter()
4. 特性

   1. closed
   2. desiredSize
5. 方法

   1. abort()
   2. close()
   3. ready
   4. releaseLock()
   5. write()
6. Related pages for Streams

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