WritableStreamDefaultWriter.desiredSize

Baseline 2022

Newly available

Since June 2022, this feature works across the latest devices and browser versions. This feature might not work in older devices or browsers.

WritableStreamDefaultWriter 接口的只读属性 desiredSize 返回填充满流的内部队列需要的大小。

一个整数。请注意,在队列已满的情况下,则可能是负数。

如果无法成功写入流(由于流发生错误或者中止入队),则该值为 null,如果流关闭,则该值为 0。

异常

TypeError

writer 的锁已被释放。

示例

js
const writableStream = new WritableStream({
  write(chunk) {
    ...
  },
  close() {
    ...
  },
  abort(err) {
    ...
  }
}, queuingStrategy);

...

const writer = writableStream.getWriter();

...

// return stream's desired size
let size = writer.desiredSize;

规范

Specification
Streams Standard
# ref-for-default-writer-desired-size⑥

浏览器兼容性

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