task_tracker/web/angular/src/app/messenger.service.ts

import {Injectable} from '@angular/core';
import {Subject} from 'rxjs';
import {MessengerState} from './messenger/messenger';

@Injectable()
export class MessengerService {

    public messengerSubject = new Subject<MessengerState>();

    show(message: string) {
        this.messengerSubject.next({
            message: message,
            hidden: false,
        });
    }

    hide() {
        this.messengerSubject.next({
            hidden: true,
        });
    }
}