angular 7:过滤后的数据不会发送给子组件

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

@Component({
  selector: 'app-parent',
  template: `
    <input type="text" [(ngModel)]="filterText">
    <app-child [filteredData]="filteredData"></app-child>
  `
})
export class ParentComponent {
  data = ['Apple', 'Banana', 'Orange'];
  filterText = '';

  get filteredData() {
    return this.data.filter(item => item.includes(this.filterText));
  }
}

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

@Component({
  selector: 'app-child',
  template: `
    <ul>
      <li *ngFor="let item of filteredData">{{ item }}</li>
    </ul>
  `
})
export class ChildComponent {
  @Input() filteredData: string[];
}