Web/API/ReadableStreamDefaultReader/releaseLock

The releaseLock() method of the ReadableStreamDefaultReader interface releases the reader's lock on the stream.

If the associated stream is errored when the lock is released, the reader will appear errored in that same way subsequently; otherwise, the reader will appear closed.

A reader’s lock cannot be released while it still has a pending read request, i.e., if a promise returned by the reader’s ReadableStreamDefaultReader.read() method has not finished. This will result in a TypeError being thrown.

Syntax

readableStreamDefaultReader.releaseLock();

Parameters

None.

Return value

undefined.

Exceptions

TypeError

The source object is not a ReadableStreamDefaultReader, or a read request is pending.

Examples

function fetchStream() {
  const reader = stream.getReader();
  
  ...

  reader.releaseLock()

  ...
}

Specifications

Specification	Status	Comment
StreamsThe definition of 'releaseLock()' in that specification.	Living Standard	Initial definition.

Browser compatibility

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.

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
releaseLock Experimental'	Chrome ?	Edge ?	Firefox Full support 65 Full support 65 Full support 57 Disabled' Disabled' From version 57: this feature is behind the dom.streams.enabled preference (needs to be set to true) and the javascript.options.streams preference (needs to be set to true). To change preferences in Firefox, visit about:config.	IE No support No	Opera ?	Safari ?	WebView Android ?	Chrome Android ?	Firefox Android Full support 65 Full support 65 Full support 57 Disabled' Disabled' From version 57: this feature is behind the dom.streams.enabled preference (needs to be set to true) and the javascript.options.streams preference (needs to be set to true). To change preferences in Firefox, visit about:config.	Opera Android ?	Safari iOS ?	Samsung Internet Android ?

Legend

Full support  

Full support

No support  

No support

Compatibility unknown  

Compatibility unknown

Experimental. Expect behavior to change in the future.'

Experimental. Expect behavior to change in the future.

User must explicitly enable this feature.'

User must explicitly enable this feature.

ReadableStreamDefaultReader.releaseLock() by Mozilla Contributors is licensed under CC-BY-SA 2.5.