WebTransport: createSendGroup() method
Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.
Note: This feature is available in Web Workers.
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".
Description
The createSendGroup() method creates a new WebTransportSendGroup associated with the WebTransport object on which it is called.
The WebTransportSendGroup is used to group together streams and datagrams created on the same WebTransport, for the purpose of controlling 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 by passing it as the sendGroup option when the object is created — see WebTransport.createUnidirectionalStream(), WebTransport.createBidirectionalStream(), and WebTransportDatagramDuplexStream.createWritable() — or by setting the object's sendGroup property afterwards — see WebTransportSendStream.sendGroup and WebTransportDatagramsWritable.sendGroup.
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,
});
Specifications
| Specification |
|---|
| WebTransport # dom-webtransport-createsendgroup |