angular:根据出生日期计算年龄

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

@Component({
  selector: 'app-age-calculator',
  template: `
    <div>
      <label for="birthdate">出生日期：</label>
      <input type="date" id="birthdate" [(ngModel)]="birthdate">
      <button (click)="calculateAge()">计算年龄</button>
    </div>
    <div *ngIf="age !== null">
      <p>年龄：{{ age }}</p>
    </div>
  `,
})
export class AgeCalculatorComponent {
  birthdate: string;
  age: number | null;

  constructor(private datePipe: DatePipe) {}

  calculateAge() {
    const currentDate = new Date();
    const formattedBirthdate = this.datePipe.transform(this.birthdate, 'yyyy');
    const formattedCurrentDate = this.datePipe.transform(currentDate, 'yyyy');
    const birthYear = parseInt(formattedBirthdate, 10);
    const currentYear = parseInt(formattedCurrentDate, 10);
    this.age = currentYear - birthYear;
  }
}