如何在Angular 5中使用返回值/s？

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

getData(): Observable<any> {
  return this.http.get('your-api-url')
    .map(response => response.json())
    .catch(error => Observable.throw(error));
}

this.yourService.getData()
  .subscribe(data => {
    // 处理返回值
  }, error => {
    // 处理错误
  });

import { Promise } from 'es6-promise';

getData(): Promise<any> {
  return this.http.get('your-api-url')
    .toPromise()
    .then(response => response.json())
    .catch(error => Promise.reject(error));
}

this.yourService.getData()
  .then(data => {
    // 处理返回值
  })
  .catch(error => {
    // 处理错误
  });