CODEWITHSUNDEEP
angulartypescript
random0620
random0620

Reputation: 1686

How can I detect when a property changes on a service?

I want components to be able to subscribe or be notified of a change on a variable in a service.

I looked into Observables but I don't think this would work because you need to complete the stream and I need to know about changes the variable over the entire time the component is active.

Does anyone know a good strategy for this?

Upvotes: 3

Views: 2588

Answers (1)

Harry Ninh
Harry Ninh

Reputation: 16718

Have you tried Subject or any of its variations?

Example using BehaviorSubject

Service:

export class MyService {
  myVariableSubject = new BehaviorSubject<number>(0);

  increase() {
    this.myVariableSubject.next(this.myVariableSubject.value + 1);
  }
}

Component:

constructor(private myService: MyService) {}

ngOnInit() {
  this.myService.myVariableSubject.subscribe((value: number) => console.log(value));
}

Warning: This might not be the most suitable solution to your problem (which you never state).

Upvotes: 10

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