web api instance method
WebTransport: createSendGroup() method
Secure context Available in workersLimited availability
The createSendGroup() method of the WebTransport interface creates and returns a WebTransportSendGroup.
Syntax
createSendGroup()
Parameters
None.
Return value
A WebTransportSendGroup object.
Exceptions
InvalidStateErrorDOMException- : Thrown if the transport’s state is
"closed"or"failed".
- : Thrown if the transport’s state is
Description
The createSendGroup() method creates a new WebTransportSendGroup associated with the WebTransport object on which it is called.
The WebTransportSendGroup object is used to group streams and/or datagrams created on the same WebTransport, to control their relative priority for sending queued bytes.
Within the same group, bytes on higher-priority streams and datagrams are sent before bytes from lower-priority ones.
The returned WebTransportSendGroup is not initially associated with any streams or datagrams.
You can associate it with a WebTransportDatagramsWritable or WebTransportSendStream object in a couple of different ways:
- By passing it as the
sendGroupoption when the object is created — seecreateUnidirectionalStream(),createBidirectionalStream(), andcreateWritable(). - By setting the object’s
sendGroupproperty afterwards — seeWebTransportSendStream.sendGroupandsendGroup.
Different groups are expected to be treated as equals for the purposes of bandwidth allocation — though the precise way bandwidth is divided between groups is implementation-defined.
Examples
Basic usage
This example creates a send group, then associates a unidirectional stream and the connection’s outgoing datagram stream with it, giving each a sendOrder that defines their relative priority.
const sendGroup = transport.createSendGroup();
const stream = await transport.createUnidirectionalStream({
sendGroup,
sendOrder: 1,
});
// Higher sendOrder: queued bytes on this stream are sent first
const datagrams = transport.datagrams.createWritable({
sendGroup,
sendOrder: 2,
});