How to use the sockjs-client function in sockjs-client

init(attempt) {
    attempt = attempt || 1;
    clearTimeout(this.timeout);

    this.socket = new SockJS('/_sock');

    this.socket.onopen = async () => {
      if (!this.isFirstTime) {
        await fetchSessionToken();
        this.eventEmitter.emit('SOCKET_RECONNECT');
      }
      this.isFirstTime = false;

      // Buffering request while Socket is still starting up
      this.buffer.forEach((req) => {
        this._doSend(req);
      });
      this.buffer = [];
    };

    this.socket.onmessage = (event) => {

created () {
    this.portfolioId = Number(this.$route.params.id)

    const socket = new SockJS('/stomp')
    this.client = Stomp.over(socket)
    this.client.debug = null
    let self = this
    this.client.connect({}, frame => {
      console.log('Connected: ' + frame)
      self.client.subscribe('/topic/solution', message => {
        const data = JSON.parse(message.body)
        // console.log(data.status)
        if (data.id === this.portfolioId) {
          self.status = data.status
          self.portfolio = data.portfolio
        }
      })
    })

    axios.get(`/api/portfolio/${this.portfolioId}`).then(res => {

initializeWebSocketConnection(){
    let ws = new SockJS(this.serverUrl);
    this.stompClient = Stomp.over(ws);
    let that = this;
    this.stompClient.connect({}, function(frame) {
      that.stompClient.subscribe("/chat", (message) => {
        if(message.body) {
          $(".chat").append("<div class="message">"+message.body+"</div>")
          console.log(message.body);
        }
      });
    });
  }

_connect(draw) {
        const { selectedSf, selectedAp, dataset } = this.props;
        var apCode = selectedAp.apCode;
        var stamp = selectedSf.toJS().stamp;

        socket = new SockJS(
            DOMAIN + 'sensing_data'
        );

        socket.onclose = () => {
            stompClient.disconnect();
            console.log('disconnected')
        };

        stompClient = Stomp.over(socket);
        stompClient.connect('manager', 'manager', function (frame) {
            console.log('Connected: ' + frame);
            stompClient.subscribe('/topic/messages' + apCode + stamp, draw);
        });
    }

export function* connectWS() {
  yield take(REQUEST_CONFIG_SUCCESS);
  const user = yield select(userConfigSelector);
  const messagesURLs = yield select(localizationSelector);
  if (!isEmpty(user) && user.token && !isEmpty(messagesURLs)) {
    const socket = yield new SockJS(
      getServerURL(messagesURLs.wsUrl) + user.token
    );
    return Stomp.over(socket);
  }
  throw new Error("Not access token or not message url");
}

initSocket() {
    const socket = new SockJS(`${WEBSOCKET_SERVER}/websocket`);
    socket.onmessage = (e) => {
      if (e.data && e.data.action === 'SYS_REPEAT_LOGIN') {
        socket.close();
        repeatLogin();
      }
    };
  }

function createSocket(url, backendOptions, callback) {
	callback(new SockJS(url, null, backendOptions));
}

constructor({
    port = 6001,
    protocol = window.location.protocol,
    hostname = window.location.hostname
  }) {
    this.connection = new SockjsClient(
      urlFormat({
        protocol,
        hostname,
        port,
        pathname: '/sockjs-node'
      })
    );
    this.connection.onclose = this.handleClose;
    this.connection.onmessage = this.handleMessage;
    this.handleConnected();
  }

function onStart() {
    socket = new SockJS(endpoint)
    socket.onopen = onOpen
    socket.onclose = onStop
    socket.onmessage = onMessage
  }