angular - typescript 传递函数作为参数

Question

  connectWebSocket() {
    const socket = new SockJS('http://localhost:8080/websocket');
    this.stompClient = Stomp.over(socket);

    const _this = this;
    this.stompClient.connect({ "Authorization" : "Bearer "+localStorage.getItem("Authorization")}, function (frame) {
      _this.stompClient.subscribe('/user/queue/notification',function (message) {
        const body = JSON.parse(message.body);
          console.log(body)
      });
    });
  }

这就是我当前连接到 websocket 的方式，但我想实现这样的目标

  connectWebSocket(func:Function) {
    const socket = new SockJS('http://localhost:8080/websocket');
    this.stompClient = Stomp.over(socket);

    const _this = this;
    this.stompClient.connect({ "Authorization" : "Bearer "+localStorage.getItem("Authorization")}, function (frame) {
      _this.stompClient.subscribe('/user/queue/notification',func());
    });
  }

然后像这样调用它

  notificationWS(hello){
    const body = JSON.parse(hello.body);
    if(body.notificationType==="FOLLOW"){
      console.log(body)
    }
  }

this.apiService.connectWebSocket(this.notificationWS.bind(this));

所以我想将函数作为参数传递给 ws 函数，但消息为空

Answer 1

问题是，在 _this.stompClient.subscribe('/user/queue/notification',func());它需要一个函数作为第二个参数。相反，您已经使用 func() 调用了该函数。并传递返回值。
试试这个( func 而不是 func() ):

  connectWebSocket(func:Function) {
    const socket = new SockJS('http://localhost:8080/websocket');
    this.stompClient = Stomp.over(socket);

    const _this = this;
    this.stompClient.connect({ "Authorization" : "Bearer "+localStorage.getItem("Authorization")}, function (frame) {
      _this.stompClient.subscribe('/user/queue/notification',func);
    });
  }