Angular / Firestore - Manipulating a AngularFirestoreDocument

Question

What I'm using

• Angular
• Firestore

What I'm trying to achieve

• Manipulate document data

• Convert the returned date into something readable

What I have

• I have a list of albums where i use snapshotChanges to return the mapped data

• I have an album that's a AngularFirestorDocument

Questions

• How can i manipulate the returned date in my album component the same way I have in the albums list component?

Album List

So this component brings back a list of albums correctly, and I can manipulate the date before i return it so that the HTML displays the correct format.

export class AlbumsListCompoment implements OnInit {

  private albumCollection: AngularFirestoreCollection<any>;
  albumns: Observable<any[]>;
  folderId: string;

  constructor(
    private readonly afs: AngularFirestore,
    private activatedRoute: ActivatedRoute,
    private router: Router
  ) {

    // Look at the url for the Folder ID and set the local variable
    this.activatedRoute.params.forEach((urlParameters) => {
      this.folderId = urlParameters['folderId'];
    });

    // Album Reference "folders/folderid/albums"
    this.albumCollection = afs.collection<any>(`folders/${this.folderId}/albums`);

    // Get the data
    this.albumns = this.albumCollection.snapshotChanges().map(actions => {
      return actions.map(a => {

        const data = a.payload.doc.data();

        // Get the date from each album
        var albumDateTimeStapm = data.album_date;

        // Convert the unix value and format it based on the users locale setting
        var albumDateISO = moment(albumDateTimeStapm).format("DD/MM/YYYY");

        // Create a new 'name' to use in the HTML binding
        data.formattedDate = albumDateISO;

        const id = a.payload.doc.id;
        return { id, ...data };
        });
       });
      }

  ngOnInit() {

  }

  }

Album

I'm not entirely show how to approach this component to perform the same manipulation. It isn't a list, it's a single document / album.

export class AlbumDetails implements OnInit {

  folderId: string;
  albumId: string;

  private albumDoc: AngularFirestoreDocument<any>;
  album: Observable<any>;

  constructor(
    private readonly afs: AngularFirestore,
    private activatedRoute: ActivatedRoute,
    private router: Router) {

    // Look at the url for the Folder and Album ID and set the local variable
    this.activatedRoute.params.forEach((urlParameters) => {
      this.folderId = urlParameters['folderId'];
      this.albumId = urlParameters['albumId'];
    });

    this.albumDoc = afs.doc<any>(`folders/${this.folderId}/albums/${this.albumId}`);
    this.album = this.albumDoc.valueChanges();


  }

  ngOnInit() {}

}

Any help would be greatly appreciated :)

Answer 1

I am not 100% sure that I understand your question. From what I understand you would like to get a handle on the returned data of the document and then change that before you display on HTML.

If that is the case you can do the following:

this.albumDoc = afs.doc<any>(`folders/${this.folderId}/albums/${this.albumId}`);
this.album = this.albumDoc.valueChanges();
this.album.subscribe(value => {
  const value1 = value.value1;
  const value2 = value.value2;
  ...
  const valueN = value.valueN;
});

If you also need metadata of the returned value (such as the id) then do the following:

this.albumDoc = afs.doc<any>
(`folders/${this.folderId}/albums/${this.albumId}`);
  this.album = this.albumDoc.snapshotChanges();
  this.album.subscribe(value => {
    const id = value.payload.id;
    const value1 = value.payload.data().value1;
    const value2 = value.payload.data().value2;
    ...
    const valueN = value.payload.data().valueN;
});

for more information on this see angularfire2 documentation