Conditionally emit observable

Question

We have an Angular 4 app with Redux (ngrx 4).

We keep the info "isLoggedIn" in the ngrx/store, and when we issue a call to the http, we have to first check if he's authenticated or not.

What we're struggling with is the implementation of the service making the http calls:

export class GetDataFromREST() {

     constructor(private http: HttpClient, private loginStore: Store) {
          this.loggedIn$ = this.loginStore.select(getLoggedIn);
     }
     ...
     public getProducts(): Observable<ProductList> {

          return /*observable that returns http.get(api) only 
                   after the loggedIn$ emits true */
     }
}

Note that logging in should not be a concern of the service - once logged in it should execute all calls that were asked from it.

Any thoughts?

Answer 1

This will achieve your requested result.

export class GetDataFromREST() {

     constructor(private http: HttpClient, private loginStore: Store) {
          this.loggedIn$ = this.loginStore.select(getLoggedIn);
     }
     ...
     public getProducts(): Observable<ProductList> {

          return this.loggedIn$.filter(Boolean).take(1).subscribe(
            () => http.get(api)
          )
     }
}