Angular2 -使用自定义验证器比较两个控件值

import { AbstractControl, Validators } from '@angular/forms';

function compare(control: AbstractControl): { [key: string]: boolean } | null {
  const value1 = control.get('control1')?.value;
  const value2 = control.get('control2')?.value;

  if (value1 !== value2) {
    return { compare: true };
  }

  return null;
}

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

@Component({
  selector: 'app-my-form',
  template: `
    <form [formGroup]="myForm">
      <input formControlName="control1" placeholder="Control 1">
      <input formControlName="control2" placeholder="Control 2">
      <div *ngIf="myForm.hasError('compare', 'group')">
        The values of Control 1 and Control 2 must be the same.
      </div>
    </form>
  `,
})
export class MyFormComponent {
  myForm: FormGroup;

  constructor(private fb: FormBuilder) {
    this.myForm = this.fb.group({
      control1: '',
      control2: '',
    }, { validator: compare });
  }
}