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WebSocket.onmessage

A handler for a WebSocket connection message event. For multiple, simultaneous event handlers, use WebSocket.addEventListener().

Example

A k6 script that initiates a WebSocket connection and sets up a handler for the message event.

JavaScript 
import { WebSocket } from 'k6/experimental/websockets';

export default function () {
  const ws = new WebSocket('ws://localhost:10000');
  ws.binaryType = 'arraybuffer';

  ws.onmessage = (data) => {
    console.log('a message received');
    console.log(data);
    ws.close();
  };
}

The preceding example uses a WebSocket echo server, which you can run with the following command:

bash 
$ docker run --detach --rm --name ws-echo-server -p 10000:8080 jmalloc/echo-server