Reference

Sending and receiving

ws.addEventListener('message', (e) => {
  if (typeof e.data === 'string') {
    console.log('text frame:', e.data);
  } else {
    // ArrayBuffer for binary frames
    console.log('binary frame:', e.data.byteLength, 'bytes');
  }
});
 
// Send a text frame
await ws.send('hello');
 
// Send a binary frame
await ws.send(new Uint8Array([0x01, 0x02, 0x03]));

send() rejects if called when readyState is not OPEN. Use await ws.opened() to gate the first send, and check ws.readyState if you keep references around for later use.

Error handling

The error event carries a non-standard .message field with the underlying cause (the standard Event carries no payload). Use it for diagnostics:

ws.addEventListener('error', (e) => {
  const msg = (e as Event & { message?: string }).message;
  console.error('mix-websocket failure:', msg);
});

If the upgrade fails before open fires, MixWebSocket transitions to CLOSED and dispatches error. opened() resolves either on open or on the failure event, so callers don't hang.

Configuration

MixWebSocket has no per-instance configuration beyond url and protocols. Tunnel-level options live on setupMixTunnel, the same shared call that mix-fetch and mix-dns use:

await setupMixTunnel({
  preferredIpr: '...',
  disableCoverTraffic: true,
});

See SetupMixTunnelOpts for the full surface.