WebSocketStream: closed property

Value

A promise, which fulfills with an object containing the following properties:

closeCode

A number representing the closing code (see the full list of CloseEvent status codes).

reason

A string representing a human-readable description of the reason why the socket connection was closed.

The promise rejects if the WebSocket connection did not close cleanly (for a clean close, the associated TCP connection must be closed after the WebSocket closing handshake is completed).

Examples

const wsURL = "wss://127.0.0.1/";
const wss = new WebSocketStream(wsURL);

wss.closed.then((result) => {
  writeToScreen(
    `DISCONNECTED: code ${result.closeCode}, message "${result.reason}"`,
  );
  console.log("Socket closed", result.closeCode, result.reason);
});

See Using WebSocketStream to write a client for a complete example with full explanation.

Specifications

Not currently a part of any specification. See https://github.com/whatwg/websockets/pull/48 for standardization progress.

Browser compatibility

See also

• WebSocketStream: integrating streams with the WebSocket API, developer.chrome.com (2020)