Matt Thomas Matt Thomas - 1 year ago 121
Javascript Question

Firebase get single item

Im trying to create a page that displays a single items data from a firebase database on a single page.

In my app.router.ts I have:

{ path: 'song/:key', component: SongDetailsComponent }

In my song-details.component.ts I have:


constructor(private _route: ActivatedRoute, private _firebaseService: FirebaseService) {}

ngOnInit() {
this._route.params.forEach((params: Params) => {
let id = params['key']; = this._firebaseService.getSong(id);

In my song-details.componenet.html I have:

{{ song | json }}

And in my firebase.service.ts I have

songsDatabaseRef: any;

constructor(private _angularFire: AngularFire) {
this.songsDatabaseRef = _angularFire.database.list('songs');

getSong(key: string) {
return this._angularFire.database.list('songs/'+key);

But when I go to the specified route for a song's detail I get an error:

error_handler.js:45 EXCEPTION: Uncaught (in promise):
Error: Error in ./SongDetailsComponent class SongDetailsComponent -
inline template:0:0 caused by: Converting circular structure to JSON

Once I added the async pipe I got the data to display but I can't access the properties of the json object.

This is the json object:

{ "artist": "Two Friends Big Bootie Mixes", "audio": "", "dateCreated": "9/10/2016", "download": "", "genres": { "bass": 0, "dubstep": 30, "future": 0, "hipHop": 0, "house": 50, "indie": 0, "pop": 0, "techno": 20 }, "image": "", "title": "2F Big Bootie Mix, Volume 10 - Two Friends", "url": "", "$key": "-KTgBcZudwBfhKcm68aa" }

When I try to get any property it says it is undefined. For example:

song title: {{(song | async | json)?.title}}

This returns null!

Any suggestions?

Answer Source

this._angularFire.database.list('songs/'+key) is an Observable (FirebaseListObservable). You need to subscribe to it to get the data.

You can use:

{{ song | async | json }}
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