sharing.ts

import {Injectable} from '@angular/core';
import {BehaviorSubject} from "rxjs";

@Injectable({
  providedIn: 'root'
})
export class DataSharingService {

  private messageSource = new BehaviorSubject('default message');
  currentMessage = this.messageSource.asObservable();

  constructor() {
  }

  changeMessage(message: string) {
    this.messageSource.next(message)
  }

}