自定义验证器Angular 2-获取返回

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

export function numberValidator(): ValidatorFn {
  return (control: AbstractControl): { [key: string]: any } | null => {
    const value = control.value;
    if (isNaN(value) || value === null) {
      return { 'number': true };
    }
    return null;
  };
}

import { Component } from '@angular/core';
import { FormBuilder, FormGroup, Validators } from '@angular/forms';
import { numberValidator } from './validators';

@Component({
  selector: 'app-my-form',
  template: `
    <form [formGroup]="myForm">
      <input formControlName="myInput">
      <div *ngIf="myForm.get('myInput').errors?.number">Invalid number</div>
    </form>
  `,
})
export class MyFormComponent {
  myForm: FormGroup;

  constructor(private fb: FormBuilder) {
    this.myForm = this.fb.group({
      myInput: ['', [Validators.required, numberValidator()]]
    });
  }
}