How to use @stomp/ng2-stompjs - 3 common examples

private getWebsocketConfig(): StompConfig {
    const stompConfig = new StompConfig();
    stompConfig.url = () => new SockJS(WebsocketService.baseWsEndpoint);
    stompConfig.heartbeat_in = 0;
    stompConfig.heartbeat_out = 20000;
    stompConfig.reconnect_delay = 1000;
    stompConfig.debug = true;

    return stompConfig;
  }

getWebsocketConfig(): StompConfig {
    const stompConfig = new StompConfig();
    stompConfig.url = () => new SockJS(baseWsEndpoint);
    stompConfig.heartbeat_in = 0;
    stompConfig.heartbeat_out = 20000;
    stompConfig.reconnect_delay = 1000;
    stompConfig.debug = true;

    return stompConfig;
  }

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)));
  }