angular-docs-cn/public/docs/_examples/user-input/ts/app/loop-back.component.ts

// #docregion
import {Component} from '@angular/core';
// #docregion loop-back-component
@Component({
  selector: 'loop-back',
  template:`
    <input #box (keyup)="0">
    <p>{{box.value}}</p>
  `
})
export class LoopbackComponent { }
// #enddocregion loop-back-component