app.component.html

<app-multiselect name="my-component" [items]="possiblePets" (itemSelected)="addPet($event)"></app-multiselect>

app.component.ts

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

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.scss']
})
export class AppComponent {
  name = '';
  pets = [];
  hasPets = false;

  possiblePets = [{ id: '1', text: 'Cat' }, { id: '2', text: 'Dog' },
  { id: '3', text: 'Parrot' }, { id: '4', text: 'Rabbit' },
  { id: '5', text: 'Turtle' }, { id: '6', text: 'Hamster' },
  { id: '7', text: 'Duck' }, { id: '8', text: 'Goose' }];

  addPet(pet): void {
    this.pets.push(pet);
    console.log(this.pets);
  }
}