类型“订阅"缺少以下属性 [英] Type 'Subscription' is missing the following properties

问题描述

编写此代码时，IDE显示错误.

IDE shows error when I write this code.

我有一个组件，该组件在ngOnInit中调用service来获取数据.服务调用另一个服务来获取一些数据，并使用它来获取数据，然后将其返回.

I have a component that calls service in ngOnInit to get the data. Service calls the other service to get some data and use it to get data then returns it.

组件:

ngOnInit() {
    const token = "abc";
    this.service.getContactPersons(token).subscribe(
      persons => this.contactPersons = persons
    );

  }

服务:

getContactPersons(token: string): Observable<ContactPerson[]> {
return this.tokenService.getParameters(token).pipe(
      switchMap((data: Params) => {
        return this.http.get<Properties>(
          this.baseUrl + `/abc/${data.param1}/properties/${data.param2}`
        );
      })
    ).subscribe((data: Properties) => data.contactPersons);
}

我收到此错误:类型'Subscription'缺少类型'Observable'的以下属性:_isScalar，源，运算符，提升和另外6个."

I've got this error: "Type 'Subscription' is missing the following properties from type 'Observable': _isScalar, source, operator, lift, and 6 more."

推荐答案

subscribe 不是与 then 等效的rxjs.具体来说，使用诺言，您可以执行 somePromise.then(doSomething).then(doSomethingElse)，但不能进行 someRxjsStream $ .subscribe(doSomething).subscribe(doSomethingElse).如果要转换数据流，则应使用几种可用的rxjs运算符之一，在本例中为 map :

subscribe is not a rxjs equivalent of then. Specifically, with promises you can do somePromise.then(doSomething).then(doSomethingElse), but you can't someRxjsStream$.subscribe(doSomething).subscribe(doSomethingElse). If you want to transform the data stream, you should use one of several available rxjs operators, and in your case it's map:

getContactPersons(token: string): Observable<ContactPerson[]> {
    return this.tokenService.getParameters(token).pipe(
        switchMap((data: Params) => this.http.get<Properties>(
            `${this.baseUrl}/abc/${data.param1}/properties/${data.param2}`)),
        map((data: Properties) => data.contactPersons));
}

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