Within my application, I am working with an array of heroes which are displayed in a list using *ngFor. When a user clicks on a hero in the list, the hero is copied to a new variable and that variable is then bound to an input field using two-way binding.
export class Hero {
id: number;
name: string;
}
Here is my hero-mock list:
import { Hero } from './heroClass';
export const HEROES: Hero[] = [
{ id: 11, name: 'Mr. Nice' },
{ id: 12, name: 'Narco' },
{ id: 13, name: 'Bombasto' },
{ id: 14, name: 'Celeritas' },
{ id: 15, name: 'Magneta' },
{ id: 16, name: 'RubberMan' },
{ id: 17, name: 'Dynama' },
{ id: 18, name: 'Dr IQ' },
{ id: 19, name: 'Magma' },
{ id: 20, name: 'Tornado' }
];
My hero component looks like this:
import { Component, OnInit } from '@angular/core';
import { Hero } from '../hero';
import { HEROES } from '../mock-heroes';
@Component({
selector: 'app-heroes',
templateUrl: './heroes.component.html',
styleUrls: ['./heroes.component.css']
})
export class HeroesComponent implements OnInit {
heroes = HEROES;
selectedHero: Hero;
constructor() { }
ngOnInit() {
}
onSelect(hero: Hero): void {
this.selectedHero = hero;
}
}
The HTML template for the component is as follows:
<h2>My Heroes</h2>
<ul class="heroes">
<li *ngFor="let hero of heroes"
[class.selected]="hero === selectedHero"
(click)="onSelect(hero)">
<span class="badge">{{hero.id}}</span> {{hero.name}}
</li>
</ul>
<div *ngIf="selectedHero">
<h2>{{ selectedHero.name | uppercase }} Details</h2>
<div><span>id: </span>{{selectedHero.id}}</div>
<div>
<label>name:
<input [(ngModel)]="selectedHero.name" placeholder="name">
</label>
</div>
</div>
An issue arises when a hero's information is edited in the input field, causing the corresponding hero in the list to also change. In AngularJS 1, this was avoided by using angular.copy(), but in Angular 2 I had to manually create a new instance of Hero to achieve deep copying:
selectedHero: new Hero();
onSelect(hero: Hero): void {
this.selectedHero.name = hero.name;
this.selectedHero.id= hero.id;
}
Are there any other methods in Angular 2 to perform deep copying without relying on jQuery or JavaScript functions?