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ReadableStreamDefaultReader: releaseLock() method

Baseline Widely available *

This feature is well established and works across many devices and browser versions. It’s been available across browsers since ⁨January 2020⁩.

* Some parts of this feature may have varying levels of support.

Note: This feature is available in Web Workers.

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.

If the reader's lock is released while it still has pending read requests then the promises returned by the reader's ReadableStreamDefaultReader.read() method are immediately rejected with a TypeError. Unread chunks remain in the stream's internal queue and can be read later by acquiring a new reader.

Syntax

releaseLock()

Parameters

None.

Return value

None (undefined).

Exceptions

TypeError: Thrown if the source object is not a ReadableStreamDefaultReader.

Examples

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

  // …

  reader.releaseLock();

  // …
}

Specifications

Specification
Streams> # ref-for-default-reader-release-lock②>

Browser compatibility

	Desktop					Mobile
	Chrome	Edge	Firefox	Opera	Safari	Chrome Android	Firefox for Android	Opera Android	Safari on IOS	Samsung Internet	WebView Android	WebView on iOS
`releaseLock`	43	79	65	30	10	43	65	30	10	4.0	43	10
`reject_pending_read_request`	105 Before version 105, `releaseLock()` throws instead of rejecting.	105 Before version 105, `releaseLock()` throws instead of rejecting.	102	91 Before version 91, `releaseLock()` throws instead of rejecting.	17	105 Before version 105, `releaseLock()` throws instead of rejecting.	102	72 Before version 72, `releaseLock()` throws instead of rejecting.	17	20.0 Before version 20.0, `releaseLock()` throws instead of rejecting.	105 Before version 105, `releaseLock()` throws instead of rejecting.	17