CODEWITHSUNDEEP
angular
dev_huesca
dev_huesca

Reputation: 516

Why is the tap operator in my service not working

Can anyone please help me and tell me why is my observable empty?

class

ionViewWillEnter(): void {
    this.notificationsSvc.fetchNotifications();
  }

  ngOnInit(): void {
    this.notificationSubscription = this.notificationsSvc.notifications.subscribe(
      (data) => {
        console.log(data) //this is empty
      }
    );
  }

service

import { Injectable } from "@angular/core";
import { BehaviorSubject } from "rxjs";
import { HttpClient } from "@angular/common/http";
import { tap } from "rxjs/operators";

@Injectable()
export class NotificationsService {
  private _notifications = new BehaviorSubject({});

  constructor(private httpClient: HttpClient) {}

  get notifications() {
    return this._notifications.asObservable();
  }

  fetchNotifications() {
    return this.httpClient
      .get("https://website.com/notifications.json")
      .pipe(tap((data) => this._notifications.next(data)));
  }
}

'notifications' getter always returns empty. I'm not sure what else to do...

Upvotes: 0

Views: 1410

Answers (1)

Berk Kurkcuoglu
Berk Kurkcuoglu

Reputation: 1523

An observable doesn't produce results unless you subscribe to it, so you need to subscribe to the Observable from fetchNotifications(), like this:

ionViewWillEnter(): void {
    this.notificationsSvc.fetchNotifications().subscribe();
}

P.S. In order to avoid this kind of issues, I would highly recommended specifying parameter and return types of your functions and fully utilizing Typescript.

Upvotes: 3

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