The congestionControl read-only property of the WebTransport interface indicates the application's preference for either high throughput or low-latency when sending data.

The value is set in the WebTransport() constructor options.

A string with one of the following values:

default

The default congestion control tuning for the transport. This is the default.

throughput

The application prefers congestion control to be tuned for throughput.

low-latency

The application prefers congestion control to be tuned for low-latency.

This example shows how to get the congestionControl preference. As this is not explicitly set in the constructor, the result is default.

const url = "https://example.com:4999/wt";
const transport = new WebTransport(url);
console.log(transport.congestionControl); // default