在Angular中访问没有表单的输入的$pristine属性？

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

@Component({
  selector: 'app-example',
  template: `
    <input type="text" (change)="onInputChange()" />
    <button (click)="checkInput()">Check Input</button>
  `,
})
export class ExampleComponent {
  isInputModified: boolean = false;

  onInputChange() {
    this.isInputModified = true;
  }

  checkInput() {
    if (this.isInputModified) {
      console.log('Input has been modified');
    } else {
      console.log('Input has not been modified');
    }
  }
}