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Display values from API In Angular 6 page

I am completely new to frontend dev and trying to display API data in an Angular 6 application and can't figure out how to do it.

I can display values in the top level of the returned details but it's the sub level details I am struggling with.

I am using an Angular 6 app using Routing.

Below is all my code

Homepage.component.html

<h2>Book ID List</h2>

<button (click)="getBooks()">Get</button>

<div *ngFor="let book of books.items">
  <p>ID: {{book.id}}</p>
</div>

I can get the 'ID'

enter image description here enter image description here

I am using a service to get the data from the test API

Service.component.ts

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

@Injectable({
  providedIn: 'root'
})

export class ApiServiceService {
  url = 'https://www.googleapis.com/books/v1/volumes?q=HTML5  Wire-frames';

  constructor(private http: HttpClient) { }

  private extractData(res: Response) {
    const body = res;
    return body || {};
  }

  getBooks(): Observable<any> {
    return this.http.get(this.url).pipe(
      map(this.extractData));
  }
}

Homepage.component.ts

import { Component, OnInit } from '@angular/core';
import { ApiServiceService } from '../../services/api-service.service';

@Component({
  selector: 'app-homepage',
  templateUrl: './homepage.component.html',
  styleUrls: ['./homepage.component.css']
})
export class HomepageComponent implements OnInit {
  books: any = [];

  constructor(private apiService: ApiServiceService) { }

  ngOnInit() { }

  getBooks() {
    this.books = [];
    this.apiService.getBooks().subscribe((data: {}) => {
      console.log(data);
      this.books = data;
    });
  }
}

At present this return the following:

enter image description here

What I want to do is display the value from the 'eBook' which is under the 'saleInfo' level. I know I need to the change the loop for each array returned in the HTML but this is where I'm stuck.

Also I'm not sure the code I have is the best, but it's working. As I said I'm new to all this, and can pull values from top level but not sublevels in the API.

Solution

  • I would recommend better naming for your service, Service.compoent.ts isn't ideal, api.service.ts is much more understandable.

    Also you can see that when you subscribe, you are using data: {}, this means that the function should expect a value of type Object, but I would use any, since you use Observable<any>

    Now for the problem.

    I have created stackblitz which does just what you wanted. I think you have got confused with the comments. You don't want to change let book of books.items to let book of books because you would be iterating over object, which you cannot do in *ngFor.