ReadableStreamBYOBReader: releaseLock() method
Baseline
2026
*
Newly available
Since March 2026, this feature works across the latest devices and browser versions. This feature might not work in older devices or browsers.
* Some parts of this feature may have varying levels of support.
Note: This feature is available in Web Workers.
The releaseLock() method of the ReadableStreamBYOBReader interface releases the reader's lock on the stream.
After the lock is released, the reader is no longer active.
The reader will appear errored if the associated stream is errored when the lock is released; 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 ReadableStreamBYOBReader.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
ReadableStreamBYOBReader.
Examples
A trivial examples is shown below. A lock is created as soon as the reader is created on the stream.
const reader = stream.getReader({ mode: "byob" });
reader.releaseLock();
Specifications
| Specification |
|---|
| Streams # ref-for-byob-reader-release-lock② |
Browser compatibility
See also
ReadableStreamBYOBReader()constructor- Using readable byte stream