如何在Angular 4中设置视图选择器发送的值的类型？

import { Component, ViewChild } from '@angular/core';
import { MyComponent } from './my-component';

@Component({
  selector: 'app-parent',
  template: `
    <app-my-component #child></app-my-component>
  `
})
export class ParentComponent {
  @ViewChild('child') childComponent: MyComponent;
}

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

@Component({
  selector: 'app-my-component',
  template: `
    <p>{{ value }}</p>
  `
})
export class MyComponent {
  @Input() value: string;
}