ReadableStreamBYOBRequest: respond() method

Limited availability

This feature is not Baseline because it does not work in some of the most widely-used browsers.

Note: This feature is available in Web Workers.

The respond() method of the ReadableStreamBYOBRequest interface is used to signal to the associated readable byte stream that the specified number of bytes were written into the ReadableStreamBYOBRequest.view.

After this method is called, the view will be transferred and no longer modifiable.

Syntax

js
respond(bytesWritten)

Parameters

bytesWritten

The number of bytes written into ReadableStreamBYOBRequest.view.

Return value

None (undefined).

Exceptions

TypeError

The request does not have an associated ReadableByteStreamController or the view buffer is not detached/cannot be transferred into.

Examples

The code below is taken from the live examples in Using readable byte stream.

The method is called by an underlying byte source as part of making a zero-copy transfer of data to fulfill a pending read request from a consumer. The underlying source first writes data into the ReadableStreamBYOBRequest.view and then calls this respond() method to indicate how much data was copied into the buffer, and cause the data to be transferred to the reader.

The code below shows this case using a hypothetical readInto() method to copy data into the view:

js
const v = controller.byobRequest.view;
bytesRead = socket.readInto(v.buffer, v.byteOffset, v.byteLength);
controller.byobRequest.respond(bytesRead);

After the operation the byobRequest.view is detached and the request should be discarded.

Specifications

Specification
Streams
# ref-for-rs-byob-request-respond①

Browser compatibility

Report problems with this compatibility data on GitHub
desktopmobileserver
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
Deno
Node.js
respond

Legend

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

Full support
Full support
No support
No support

See also