How do I pass an object to Angular with the @ Output() decorator?

The object transfer is registered in this file, but the code does not work correctly, "[object Object] " is output, how can I fix it? Please help me figure it out

//child.component.ts

import { Component, Output, EventEmitter } from '@angular/core';


@Component({
  selector: 'child',
  template: '<div><input class="form-control" [(ngModel)]="user" placeholder = "Введите сообщение" />
  <button class="btn btn-default" (click)="adding(user, bot)">Отправить</button></div>',
  styleUrls: ['./child.component.css']
})
export class ChildComponent {

@Output('AddMessage') addMessage = new EventEmitter<object>()

public adding(user_mes: string, bot_mes: string) {

this.addMessage.emit({user_mes, bot_mes});

}

}

//two.component.ts

import { Component, Input, EventEmitter, Output } from '@angular/core';

@Component({
  selector: 'two',
  template: `<h4>Список сообщений</h4>
  <ul *ngFor="let msg of message"><li>{{msg.user}}</li><li>{{msg.bot}}</li></ul>`,
  styles: [ '' ]
 })
 export class TwoComponent  {
 @Input() message: string[];
 }

//app.component.ts

import { Component } from '@angular/core';

class Messages {

  user: string;
  bot: string;

constructor(_user: string, _bot: string) {

    this.user = _user;
    this.bot = _bot;

  }

}

@Component({
  selector: 'my-app',
  template: '<two [message]="message"></two>
  <child (AddMessage)="addMessage($event)"></child>',
  styleUrls: ['./app.component.css']
})
export class AppComponent {

  public message: Messages[] = [];

  addMessage(user: string, bot: string) {
    if (user == null) {
      return;
    }
   this.message.push(new Messages(user, bot));
  }
  }