ReadableStreamBYOBReader: closed property

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.

Note: This feature is available in Web Workers.

The closed read-only property of the ReadableStreamBYOBReader interface returns a Promise that fulfills when the stream closes, or rejects if the stream throws an error or the reader's lock is released.

This property enables you to write code that responds to an end to the streaming process.

Value

A Promise.

Examples

The code below shows the pattern for handling the closed/error state of a BYOBReader.

js
const reader = stream.getReader({ mode: "byob" });
reader.closed
  .then(() => {
    // Resolved - code to handle stream closing
  })
  .catch(() => {
    // Rejected - code to handle error
  });

Specifications

Specification
Streams
# ref-for-generic-reader-closed②

Browser compatibility

desktop mobile server
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
Bun
Deno
Node.js
closed
Chrome – Full support
Chrome 89 (Release date: 2021-03-02)
footnote Full support
Edge – Full support
Edge 89 (Release date: 2021-03-04)
footnote Full support
Firefox – Full support
Firefox 102 (Release date: 2022-06-28)
footnote Full support
Opera – Full support
Opera 75 (Release date: 2021-03-24)
footnote Full support
Safari – Full support
Safari 26.4 (Release date: 2026-03-24)
footnote Full support
Chrome Android – Full support
Chrome Android 89 (Release date: 2021-03-02)
footnote Full support
Firefox for Android – Full support
Firefox for Android 102 (Release date: 2022-06-28)
footnote Full support
Opera Android – Full support
Opera Android 63 (Release date: 2021-04-16)
footnote Full support
Safari on iOS – Full support
Safari on iOS 26.4 (Release date: 2026-03-24)
footnote Full support
Samsung Internet – Full support
Samsung Internet 15 (Release date: 2021-08-13)
footnote Full support
WebView Android – Full support
WebView Android 89 (Release date: 2021-03-02)
footnote Full support
WebView on iOS – Full support
WebView on iOS 26.4 (Release date: 2026-03-24)
footnote Full support
Bun – Full support
Bun 1 (Release date: 2023-09-08)
footnote Full support
Deno – Full support
Deno 1.16 (Release date: 2021-11-08)
footnote Full support
Node.js – Full support
Node.js 16.5 (Release date: 2021-07-14)
footnote Full support

Legend

Tip: you can click/tap on a cell for more information.

Full support
Full support

See also