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const ws = new WebSocket('ws://example.org');

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ws.addEventListener('open', () => {
  // Send a message to the WebSocket server
  ws.send('Hello!');
});

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ws.addEventListener('message', event => {
  // The `event` object is a typical DOM event object, and the message data sent
  // by the server is stored in the `data` property
  console.log('Received:', event.data);
});

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// Establish a WebSocket connection to the echo server
const ws = new WebSocket('wss://echo.websocket.org');
// Add a listener that will be triggered when the WebSocket is ready to use
ws.addEventListener('open', () => {
  const message = 'Hello!';
  console.log('Sending:', message);
  // Send the message to the WebSocket server
  ws.send(message);
});
// Add a listener in order to process WebSocket messages received from the server

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const ws = new WebSocket('ws://localhost:3210', ['json', 'xml']);
ws.addEventListener('open', () => {
  const data = { message: 'Hello from the client!' }
  const json = JSON.stringify(data);
  ws.send(json);
});
ws.addEventListener('message', event => {
  const data = JSON.parse(event.data);
  console.log(data);
});

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socket.on('data', buffer => {
  const message = parseMessage(buffer);
  if (message) {
  // For our convenience, so we can see what the client sent
  console.log(message);
  // We'll just send a hardcoded message in this example 
  socket.write(constructReply({ message: 'Hello from the server!' })); 
  } else if (message === null) { 
      console.log('WebSocket connection closed by the client.'); 
  }

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function parseMessage (buffer) {
  const firstByte = buffer.readUInt8(0);
  const isFinalFrame = Boolean((firstByte >>> 7) & 0×1); 
  const [reserved1, reserved2, reserved3] = [ Boolean((firstByte >>> 6) & 0×1), Boolean((firstByte >>> 5) & 0×1), Boolean((firstByte >>> 4) & 0×1) ]; 
  const opCode = firstByte & 0xF; 
  // We can return null to signify that this is a connection termination frame 
  if (opCode === 0×8) 
     return null; 
  // We only care about text frames from this point onward 
  if (opCode !== 0×1) 

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let maskingKey;
if (isMasked) {
  maskingKey = buffer.readUInt32BE(currentOffset);
  currentOffset += 4;
}

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// Allocate somewhere to store the final message data
const data = Buffer.alloc(payloadLength);
// Only unmask the data if the masking bit was set to 1
if (isMasked) {
  // Loop through the source buffer one byte at a time, keeping track of which
  // byte in the masking key to use in the next XOR calculation
  for (let i = 0, j = 0; i < payloadLength; ++i, j = i % 4) {
  // Extract the correct byte mask from the masking key
    const shift = j == 3 ? 0 : (3 - j) << 3; 
    const mask = (shift == 0 ? maskingKey : (maskingKey >>> shift)) & 0xFF;

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function parseMessage (buffer) {
  // …all of the above, then:
  const json = data.toString('utf8'); return JSON.parse(json);
}