javascript - 关于ng2的双向绑定问题

问题描述

问 题

import { Component } from '@angular/core';
export class Hero {
    id: number;
    name: string;
}
@Component({
    selector: 'my-app',
    template: `
    <h1>{{title}}</h1>
    <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}} details!</h2>
      <div><label>id: </label>{{selectedHero.id}}</div>
      <div>
        <label>name: </label>
        <input [(ngModel)]="selectedHero.name" placeholder="name"/>
      </div>
    </div>
  `,
    styles: [`
    .selected {
      background-color: #CFD8DC !important;
      color: white;
    }
    .heroes {
      margin: 0 0 2em 0;
      list-style-type: none;
      padding: 0;
      width: 15em;
    }
    .heroes li {
      cursor: pointer;
      position: relative;
      left: 0;
      background-color: #EEE;
      margin: .5em;
      padding: .3em 0;
      height: 1.6em;
      border-radius: 4px;
    }
    .heroes li.selected:hover {
      background-color: #BBD8DC !important;
      color: white;
    }
    .heroes li:hover {
      color: #607D8B;
      background-color: #DDD;
      left: .1em;
    }
    .heroes .text {
      position: relative;
      top: -3px;
    }
    .heroes .badge {
      display: inline-block;
      font-size: small;
      color: white;
      padding: 0.8em 0.7em 0 0.7em;
      background-color: #607D8B;
      line-height: 1em;
      position: relative;
      left: -1px;
      top: -4px;
      height: 1.8em;
      margin-right: .8em;
      border-radius: 4px 0 0 4px;
    }
  `]
})
export class AppComponent {
    title = 'Tour of Heroes';
    heroes = HEROES;
    selectedHero: Hero;
    onSelect(hero: Hero) { 
        this.selectedHero = hero;
        console.log(this.selectedHero); console.log(HEROES)
     }
}
var 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" }
];

其实就是官方demo的例子。我不明白：
input框里和selectedHero.name双向绑定了，改了selectedHero.name以后，为什么列表上的hero也会变？heroes和selectedHero.name没有关系，heroes不变ngFor的循环就不会变吧？

解决方案

引用的是同一个对象

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