输入'Observable <Response | Observable <Response >>'不能分配给'Observable <Response>'类型

Question

我有一个简单的服务,内容如下:

import { Injectable } from '@angular/core';
import { Http, Response } from '@angular/http';

import 'rxjs/add/observable/throw';
import 'rxjs/add/operator/catch';
import 'rxjs/add/operator/map';
import { Observable } from 'rxjs/Observable';

@Injectable()
export class AddressService {

  constructor(private http: Http) { }

  getAnything = (): Observable<Response> => {
    return this.http.get('https://my_api.com')
      .map(this.handleSuccess)
      .catch(this.handleError);
  }

  handleError = (error: Response): Observable<Response> => {
    return Observable.throw(error || 'Server Error');
  }

  handleSuccess = (response: Response): Observable<Response> => {
    let body;

    if (response.text()) {
      body = response.json();
    }

    return body || {};
  }
}

它工作得很好,直到我将Typescript从2.3.4升级到2.4.1.

现在,升级后,我收到了奇怪的错误:

Type 'Observable<Response | Observable<Response>>' is not assignable to type 'Observable<Response>'

这有什么意义？TS 2.4.x中的哪些更改使我的应用程序停止正常工作？

Answer 1

TypeScript 2.4引入了更好的泛型检查.它突出显示了应该修复的代码中的错误.

例如,返回类型与返回的内容handleSuccess不匹配; 它返回一个匿名对象,但键入为返回Observable<Response>.因为它正在使用map,你最终会得到一个被输入的组合的observable Observable<Response | Observable<Response>>.

您看到的错误是真实的,应该修复.