无法在Angular Service中为对象的属性分配值

Question

Service has the empty object "message". I assign its property values through "add()" method. Logs show that values are assigned. But when I want to get it from the component directly or through a getter, the properties are still undefined, which is confirmed by the log() method in the getter.

I am new in Angular, as well as in TS, so I guess I don`t see an obvious mistake. Thank you in advance for any help.

Message object:

export class Message {
  messageText: string;
  messageStatus: MessageStatus;
}

MessageStatus enum:

export enum MessageStatus {
  INFO,
  SUCCESS,
  ERROR,
  WARN
}

Service:

import {Injectable} from '@angular/core';
import {Message} from '../../model/message';
import {log} from 'util';

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

  private message: Message = new Message();

  constructor() { }

  public add(message: Message): void {
    this.message = message
    log('MESSAGE in add: ' + this.message.messageText +', STATUS in add: ' + this.message.messageStatus);
  }

  public getMessage(): Message {
    log('MESSAGE in get: ' + this.message.messageText +', STATUS in get: ' + this.message.messageStatus);
    return this.message;
  }

  public clear(): void {
    this.message = new Message();
  }
}

Component:

import { Component, OnInit } from '@angular/core';
import {MessageService} from '../../service/messages/message.service';
import {MessageStatus} from '../../service/messages/messageStatus';

@Component({
  selector: 'app-messages',
  template: `    
    <div class="message-position" *ngIf="messageService.getMessage().messageText">
      <div [ngClass]="{
        'alert alert-info': messageService.getMessage().messageStatus === MessageStatus.INFO,
        'alert alert-success': messageService.getMessage().messageStatus === MessageStatus.SUCCESS,
        'alert alert-danger': messageService.getMessage().messageStatus === MessageStatus.ERROR,
        'alert alert-warning': messageService.getMessage().messageStatus === MessageStatus.WARN
      }">
        {{messageService.getMessage().messageText}}
        <button class="btn btn-primary" (click)="messageService.clear()">Ok</button>
      </div>

    </div>`,
  styleUrls: ['./messages.component.scss']
})
export class MessagesComponent{
  constructor(public messageService: MessageService) { }
}

log() output in add(), shows that object properties received values:

25 Nov 19:05:22 - MESSAGE in add: Customer not found, STATUS in add: 3

log() output in getMessage(), object properties are still underfined:

25 Nov 19:05:22 - MESSAGE in get: undefined, STATUS in get: undefined

UPDATE:

The method that calls add(). Placed in different class:

private messageService: MessageService = new MessageService();
private message: Message = new Message();

logResponce(messageText: string, messageStatus: MessageStatus): void {
    this.message.messageText = messageText;
    this.message.messageStatus = messageStatus;
    this.messageService.add(this.message);
  }

Answer 1

new MessageService()

that creates a new instance of the service. You don't want that. You want to use the singleton instance that is created by Angular and injected in the component.