The byobRequest
read-only property of the ReadableByteStreamController
interface returns the current BYOB request, or null
if there are no pending requests.
An underlying byte source should check this property, and use it to write data to the stream if it exists (rather than using ReadableByteStreamController.enqueue()
). This will result in an efficient zero-byte transfer of the data to the consumer.
A ReadableStreamBYOBRequest
object instance, or null
.
The example in Using readable byte streams > Creating a readable socket push byte stream shows how you use a byobRequest
to transfer data (if it exists), or otherwise copy the data to the stream's internal queues using ReadableByteStreamController.enqueue()
.
The relevant code is reproduced below. If the byobRequest
exists, data is read into controller.byobRequest.view
, and then ReadableStreamBYOBRequest.respond()
is called to signal the amount of data that is ready to transfer.
if (controller.byobRequest) {
const v = controller.byobRequest.view;
bytesRead = socket.readInto(v.buffer, v.byteOffset, v.byteLength);
if (bytesRead === 0) {
controller.close();
}
controller.byobRequest.respond(bytesRead);
} else {
}