ReadableStreamBYOBRequest: respondWithNewView() method
The respondWithNewView()
method of the ReadableStreamBYOBRequest
interface specifies a new view that the consumer of the associated readable byte stream should write to instead of ReadableStreamBYOBRequest.view
.
The new view must be a TypedArray
or a DataView
that provides a view onto the same backing memory region as ReadableStreamBYOBRequest.view
.
After this method is called, the view that was passed into the method will be transferred and no longer modifiable.
The method is intended for use cases where an underlying byte source needs to transfer a byobRequest.view
internally before finishing its response.
For example, the source may transfer the BYOB view to a separate worker thread, and wait for the worker to transfer it back once it has been filled.
Syntax
js
respondWithNewView(view)
Parameters
view
-
A
TypedArray
or aDataView
that the consumer of the associated readable byte stream should write to instead ofReadableStreamBYOBRequest.view
.This must be a view onto the same backing memory region as
ReadableStreamBYOBRequest.view
and occupy the same or less memory. Specifically, it must be either the view's buffer or a transferred version, must have the samebyteOffset
, and abyteLength
(number of bytes written) that is less than or equal to that of the view.
Return value
None (undefined
).
Exceptions
TypeError
-
Thrown if the source object is not a
ReadableStreamBYOBRequest
, or there is no associated controller, or the associated internal array buffer is non-existent or detached. It may also be thrown if theview
is zero-length when there is an active reader, or non-zero when called on a closed stream. RangeError
-
Thrown if the new
view
does not match the backing memory region ofReadableStreamBYOBRequest.view
. For example, it is not the same buffer (or a transferred version), has a differentbyteOffset
, or is larger than the memory available to the backing view.
Examples
The view to be transferred must be of the same type as ReadableStreamBYOBRequest.view
, have the same underlying buffer and byte offset, and be the same or smaller byteLength.
For example, we might define the view and respond as shown below:
js
const v = controller.byobRequest.view;
bytesRead = socket.readInto(v.buffer, v.byteOffset, v.byteLength);
byobRequest.respondWithNewView(
byobRequest.view.subarray(v.byteOffset, bytesRead)
);
Specifications
Specification |
---|
Streams Standard # ref-for-rs-byob-request-respond-with-new-view① |
Browser compatibility
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