WebTransportError: source property

Baseline 2026

Newly available

Since March 2026, this feature works across the latest devices and browser versions. This feature might not work in older devices or 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 source read-only property of the WebTransportError interface returns an enumerated value indicating the source of the error.

Value

An enumerated value; can be either stream or session.

Examples

const url = "not-a-url";

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

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

    // …
  } catch (error) {
    const msg = `Transport initialization failed.
                 Reason: ${error.message}.
                 Source: ${error.source}.
                 Error code: ${error.streamErrorCode}.`;
    console.log(msg);
  }
}