ReadableStreamDefaultReader: closed property

Note: This feature is available in Web Workers.

The closed read-only property of the ReadableStreamDefaultReader 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.



In this snippet, a previously-created reader is queried to see if the stream has been closed. When it is closed, the promise fulfills and the message is logged to the console.

reader.closed.then(() => {
  console.log("reader closed");


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

Browser compatibility

BCD tables only load in the browser

See also