CODEWITHSUNDEEP
angulartypescriptobjectrxjsbehaviorsubject
Prabesh
Prabesh

Reputation: 373

How to create behavior subject for object and subscribe to it on another component?

I created a behaviour subject in a service class.

public personObject: BehaviorSubject<any> =
    new BehaviorSubject<any>({ personId: 1, name: 'john doe' });

On a component that imports this service, i subscribed this behaviour subject like this:

this._subscription.add(
    this._bankService.personObject.subscribe(data => {
        this.personObject = data;
        console.log(data);
    })
);

But I am not able to get exact dataset in the behaviour subject.

Edit I forgot to mention that I used ViewContainerRef to create my sibling component which I added to an answer with a few comments.

Upvotes: 6

Views: 45073

Answers (3)

Roman Bondar
Roman Bondar

Reputation: 103

(Sender) In the component where you change object properties:

import { StoreService } from '../../services/store.service';

constructor(private _storeService: StoreService) {}

ngOnInit(): void {
    let person = { personId: 0, name: '' };
    this._storeService.personObject.subscribe( value => {
      person.personId = value.personId; // set value personId from service
    } );
    this._storeService.order.next({...person, name: 'somebody'  } ); // set new value for name property
  }

(Receptor) In the component where you subscribe to personObject:

import { StoreService } from '../../services/store.service'; // service file with personObject variable

constructor(private _storeService: StoreService) {}

this._storeService.personObject.subscribe( value => {
  console.log(value);
} );

Upvotes: 1

Dmitry Grinko
Dmitry Grinko

Reputation: 15204

Service

@Injectable()
export class DataService {

  private _dataListSource: BehaviorSubject<IData[]> = new BehaviorSubject([]);
  dataList: Observable<IData[]> = this._dataListSource.asObservable().distinctUntilChanged();

  getDataList(): Observable<any> {
      return this.httpService.get('/data').map(res => {
          this._dataListSource.next(res);
      });
  }
}

TS file

export class DataComponent implements OnInit {

    public dataList$: Observable<IData[]>;

    constructor(public dataService: DataService) {}

    ngOnInit() {
        this.dataList$ = this.dataService.dataList;
        this.dataService.getDataList().subscribe();
    }
}

HTML file

<div *ngIf="dataList$ | async; let dataList; ">
    <div *ngFor="let data of dataList">
        {{ data | json}}
    </div>
</div>

Upvotes: 13

Prabesh
Prabesh

Reputation: 373

I forgot to mention that I was using I was using ViewContainerRef to create a sibling component and it turns out behavior subject does not work the same way with component created using ViewContainerRef.

Other wise Behaviour subjects of any object work exactly like with number or string. I used @Input to send data to component for now.

Upvotes: 1

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