如何在Angular中验证11位数字的输入域？

<input type="text" [formControl]="myFormControl">

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

@Component({
  selector: 'app-my-component',
  templateUrl: './my-component.component.html',
  styleUrls: ['./my-component.component.css']
})
export class MyComponent {
  myFormControl = new FormControl('', [
    Validators.pattern('^[0-9]{11}$')
  ]);
}

<input type="text" [formControl]="myFormControl">
<div *ngIf="myFormControl.invalid && (myFormControl.dirty || myFormControl.touched)">
  <div *ngIf="myFormControl.errors.pattern">
    输入必须为11位数字。
  </div>
</div>