Angular 11 Custom Validation Tutorial With Example

In this tutorial, we will explain to you how to create custom validation in angular 11(Angular 11 Custom Validation Tutorial with Example). In this example, we will use the reactive forms module for customized validation.

Create new angular app

We will create a new angular app using the following command.

ng new myapp
cd myapp

Import module in angular

In this step, we need to add a module into the src/app/app.module.ts file.

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

@NgModule({

  declarations: [
    AppComponent
  ],

  imports: [
    BrowserModule,
    FormsModule,
    ReactiveFormsModule

  ],
  providers: [],
  bootstrap: [AppComponent]

})

export class AppModule { }

Update view file in angular

In this step, we have created a simple form with some fields. when we click on the submit button at that time check the validation. if validation is false then will be shown an error message.

src/app/app.component.html

<div class="container">
  <h2>Angular 11 Custom Validation Tutorial with Example</h2>
	<form [formGroup]="form" (ngSubmit)="submit()">
		<div class="form-group">
			<label for="email">Email</label>
			<input formControlName="email" id="email" type="email" class="form-control">
			<div *ngIf="validCheck.email.touched && validCheck.email.invalid" class="alert alert-danger">
				<div *ngIf="validCheck.email.errors.required">Email is required.</div>
				<div *ngIf="validCheck.email.errors.email">Please enter a valid email.</div>
			</div>
		</div>
		<div class="form-group">
			<label for="password">Password</label>
			<input formControlName="password" id="password" type="password" class="form-control">
			<div *ngIf="validCheck.password.touched && validCheck.password.invalid" class="alert alert-danger">
				<div *ngIf="validCheck.password.errors.required">Password is required.</div>
				<div *ngIf="validCheck.password.errors.minlength">Password must be at least 6 characters</div>
			</div>
		</div>
		<button class="btn btn-primary" type="submit">Submit</button>
	</form>
</div>

Update component in angular

src/app/app.component.ts

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

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

})

export class AppComponent {

  form = new FormGroup({
    email: new FormControl('', [Validators.required, Validators.email]),
    password: new FormControl('',[ Validators.required, , Validators.minLength(6)])
  });
  
  get validCheck(){
    return this.form.controls;
  }
  
  submit(){
    console.log(this.form.value);
  }
}

Run Our Angular Application

Now we will run our Angular application using the below command.

ng serve