How to use the websocket.w3cwebsocket.OPEN function in websocket

return new Promise((_resolve, _reject) => {
                                        if (ws.readyState !== WS.OPEN) {
                                            //we may have closed whilst waiting for the token.
                                            //always retry.
                                            emit({
                                                name: 'ws:close-before-send',
                                                data: null,
                                            });

                                            return connectionClosedBeforeSend;
                                        }

                                        ref();

                                        let called = false;
                                        const callback = (err, data) => {
                                            if (called) {
                                                return;

self.on('finish', function() {
    if (self.socket && self.socket.readyState === W3CWebSocket.OPEN) {
      self.socket.send(JSON.stringify(closingMessage));
    } else {
      self.once('connect', function() {
        self.socket.send(JSON.stringify(closingMessage));
      });
    }
  });

self.on('finish', function() {
    if (self.socket && self.socket.readyState === W3CWebSocket.OPEN) {
      self.socket.send(JSON.stringify(closingMessage));
    } else {
      self.once('connect', function() {
        self.socket.send(JSON.stringify(closingMessage));
      });
    }
  });