Angular 6:对数组的每个元素进行2次api调用

ng new my-app

import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { Observable } from 'rxjs';

@Injectable({
  providedIn: 'root'
})
export class ApiService {
  constructor(private http: HttpClient) { }

  public callApi(element: any): Observable<any> {
    // 发送第一次API调用
    return this.http.get('https://api.example.com/endpoint1/' + element).pipe(
      mergeMap(response1 => {
        // 发送第二次API调用
        return this.http.get('https://api.example.com/endpoint2/' + response1);
      })
    );
  }
}

import { Component } from '@angular/core';
import { ApiService } from './api.service';

@Component({
  selector: 'app-root',
  template: `
    <div *ngFor="let element of elements">
      {{ element }}
    </div>
  `
})
export class AppComponent {
  elements: any[] = ['element1', 'element2', 'element3'];

  constructor(private apiService: ApiService) {
    this.callApiForElements();
  }

  private callApiForElements(): void {
    this.elements.forEach(element => {
      this.apiService.callApi(element).subscribe(response => {
        // 处理API调用的响应数据
        console.log(response);
      });
    });
  }
}