How to convert JSON object to an Typescript array?

Question

I have an API request which returns the following:

{"page": 1,
  "results": [
    {
      "poster_path": "/9O7gLzmreU0nGkIB6K3BsJbzvNv.jpg",
      "adult": false,
      "overview": "Framed in the 1940s for the double murder of his wife and her lover, upstanding banker Andy Dufresne begins a new life at the Shawshank prison, where he puts his accounting skills to work for an amoral warden. During his long stretch in prison, Dufresne comes to be admired by the other inmates -- including an older prisoner named Red -- for his integrity and unquenchable sense of hope.",
      "release_date": "1994-09-10",
      "genre_ids": [
        18,
        80
      ],
      "id": 278,
      "original_title": "The Shawshank Redemption",
      "original_language": "en",
      "title": "The Shawshank Redemption",
      "backdrop_path": "/xBKGJQsAIeweesB79KC89FpBrVr.jpg",
      "popularity": 5.446135,
      "vote_count": 5250,
      "video": false,
      "vote_average": 8.32
    },
    {
      "poster_path": "/lIv1QinFqz4dlp5U4lQ6HaiskOZ.jpg",
      "adult": false,
      "overview": "Under the direction of a ruthless instructor, a talented young drummer begins to pursue perfection at any cost, even his humanity.",
      "release_date": "2014-10-10",
      "genre_ids": [
        18,
        10402
      ],
      "id": 244786,
      "original_title": "Whiplash",
      "original_language": "en",
      "title": "Whiplash",
      "backdrop_path": "/6bbZ6XyvgfjhQwbplnUh1LSj1ky.jpg",
      "popularity": 9.001948,
      "vote_count": 2072,
      "video": false,
      "vote_average": 8.28
    },

I would like to show the fetched movie title after the button click with the following code:

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

@Component({
  selector: 'http',
  template: `

<button (click)="makeRequest()">Make Request</button>

<table class="table table-striped">
      <thead>
        <tr>
          <th>Title</th>
         </tr>
      </thead>

        <tbody>
        <tr *ngFor="let movie of data">
          <td>{{movie.title}}</td>
        </tr>

      </tbody>
    </table>
`
})
export class AppComponent {

  data: Object;

  constructor(public http: Http) {
  }
  makeRequest(): void {

    this.http.request('http://api.themoviedb.org/3/movie/top_rated?api_key=API-KEY')
      .subscribe((res: Response) => {
        this.data = res.json();

      });
  }

}

My problem is that I get an error message which says I can only loop through Arrays, and my data is an Object. How can I convert my Object to Array in typescript, and show the title of the movie in the the table?

Solution 1

That's correct, your response is an object with fields:

{
    "page": 1,
    "results": [ ... ]
}

So you in fact want to iterate the results field only:

this.data = res.json()['results'];

... or even easier:

this.data = res.json().results;

Solution 2

To convert any JSON to array, use the below code:

const usersJson: any[] = Array.of(res.json());

Solution 3

You have a JSON object that contains an Array. You need to access the array results. Change your code to:

this.data = res.json().results