更好、更有效地以角度反应形式显示错误消息，而无需使用多个*ngIf

import { Component } from '@angular/core';
import { FormGroup, FormControl, Validators } from '@angular/forms';

@Component({
  selector: 'app-my-form',
  template: `
    <form [formGroup]="myForm">
      <input type="email" formControlName="email">
      <div *ngIf="myForm.get('email').invalid && myForm.get('email').touched">
        <div *ngIf="myForm.get('email').errors.required">Email is required</div>
        <div *ngIf="myForm.get('email').errors.email">Invalid email format</div>
      </div>
    </form>
  `,
})
export class MyFormComponent {
  myForm: FormGroup;

  constructor() {
    this.myForm = new FormGroup({
      email: new FormControl('', [Validators.required, Validators.email]),
    });
  }
}