Angular pubSub service

event-bus.service.ts

import { Injectable } from '@angular/core';
import { Observable, ReplaySubject } from 'rxjs';

@Injectable({
  providedIn: 'root'
})
export class EventBusService {
  private readonly events: { [eventName: string]: ReplaySubject<any> } = {};

  public sub(event: string): Observable<any> {
    if (!this.events[event]) {
      this.events[event] = new ReplaySubject<any>();
    }

    return this.events[event].asObservable();
  }

  public pub(event: string, eventObject?: any): void {
    if (!this.events[event]) return;

    this.events[event].next(eventObject);
  }
}