W3cubDocs

/DOM

ReadableStreamDefaultController.desiredSize

Draft
This page is not complete.

This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The desiredSize getter property of the ReadableStreamDefaultController interface returns the desired size required to fill the stream's internal queue.

Syntax

var desiredSize = readableStreamDefaultControllerInstance.desiredSize;

Value

An integer. Note that this can be negative if the queue is over-full.

Examples

The A readable stream with an underlying push source and backpressure support example in the spec provides a good example of using desiredSize to manually detect when the stream is full and apply backpressure, and also of using ReadablestreamDefaultController.error() to manually trigger a stream error if another part of the system it relies on fails.

Specifications

Specification Status Comment
Streams
The definition of 'desiredSize' in that specification.
Living Standard Initial definition.

Browser compatibilityUpdate compatibility data on GitHub

Desktop
Chrome Edge Firefox Internet Explorer Opera Safari
Basic support ? ? ? ? ? ?
Mobile
Android webview Chrome for Android Edge Mobile Firefox for Android Opera for Android iOS Safari Samsung Internet
Basic support ? ? ? ? ? ? ?

© 2005–2018 Mozilla Developer Network and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/API/ReadableStreamDefaultController/desiredSize