WebTransport: ready property

Limited availability

This feature is not Baseline because it does not work in some of the most widely-used browsers.

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 ready read-only property of the WebTransport interface returns a promise that resolves when the transport is ready to use.

This promise is created when the WebTransport object is created and is resolved when a connection is established. Accessing or awaiting this promise does not trigger any action; it only allows actions to be taken when the transport is ready, similar to listening to an event.

Value

A Promise that resolves to undefined.

Examples

const url = "https://example.com:4999/wt";

async function initTransport(url) {
  // Initialize transport connection
  const transport = new WebTransport(url);

  // The connection can be used once ready fulfills
  await transport.ready;

  // …
}

// …

async function closeTransport(transport) {
  // Respond to connection closing
  try {
    await transport.closed;
    console.log(`The HTTP/3 connection to ${url} closed gracefully.`);
  } catch (error) {
    console.error(`The HTTP/3 connection to ${url} closed due to ${error}.`);
  }
}