How to use the @stomp/ng2-stompjs.StompService function in @stomp/ng2-stompjs

connectStompService(config: any) {
    const stompUrl = config.protocol + '://' + config.host + ':' + config.port + config.endpoint;
    const stompConfig: StompConfig = {
      url: stompUrl,
      headers: {
        login: '',
        passcode: ''
      },
      heartbeat_in: 0,
      heartbeat_out: 20000,
      reconnect_delay: 5000,
      debug: true
    };
    this.stompService = new StompService(stompConfig);
    this.stompService.subscribe(config.likesTopic).subscribe(like => this.likes.unshift(JSON.parse(like.body)));
  }