ReadableStream: locked property

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since ⁨January 2019⁩.

Note: This feature is available in Web Workers.

The locked read-only property of the ReadableStream interface returns whether or not the readable stream is locked to a reader.

A readable stream can have at most one active reader at a time, and is locked to that reader until it is released. A reader might be obtained using ReadableStream.getReader() and released using the reader's releaseLock() method.

Value

A boolean value indicating whether or not the readable stream is locked.

Examples

const stream = new ReadableStream({
  // …
});

const reader = stream.getReader();

stream.locked;
// should return true, as the stream has been locked to a reader