将observable <string>转换为字符串打字稿

Question

在ngOnInit（）上，我正在从以下代码中读取查询参数。如何将可观察对象转换为字符串？

  constructor(private router: ActivatedRoute) { }

  textToDisplay: Observable<string>;

  ngOnInit() {
    this.textToDisplay = this.router
      .queryParamMap
      .pipe(map(params => params.get('session_id') || 'None'));
  }

Answer 1

使用订阅方法。看下面的例子。

 this.route.queryParams.subscribe(params => {
    console.log(params); // {order: "popular"}
    this.order = params.order;
    console.log(this.order); // popular
 });

Answer 2

您可以尝试以下解决方案：

constructor(private router: ActivatedRoute) { }

  textToDisplay: Observable<string>;

  ngOnInit() {
     this.router.queryParams.subscribe(resp => {
        if (resp.status) {
          //get response data
          this.textToDisplay = resp
        }
      });
  }