How to Create Custom Validators in Angular Reactive Forms

Reactive Forms in Angular provide a powerful way to manage form inputs, validations, and user interactions. While Angular offers built-in validators like Validators.required, Validators.email, and Validators.minLength, sometimes, you need custom validation to meet specific business requirements.

In this article, we’ll explore how to create custom validators in Angular’s Reactive Forms.

1. Setting Up a Reactive Form

First, let’s create a simple form using Reactive Forms. Ensure you have the ReactiveFormsModule imported in your module:

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { ReactiveFormsModule } from '@angular/forms';
import { AppComponent } from './app.component';

@NgModule({
  declarations: [AppComponent],
  imports: [BrowserModule, ReactiveFormsModule],
  providers: [],
  bootstrap: [AppComponent],
})
export class AppModule {}

Now, let’s define our form in app.component.ts:

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

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls…