Angular 12 Reactive Forms Validation Example

By Hardik Savani June 3, 2021 Category : Angular

Hello,

This tutorial will give you example of angular 12 reactive forms validation. This tutorial will give you simple example of angular 12 forms validation example. In this article, we will implement a angular 12 reactive forms example. We will look at example of reactive form validation in angular 12.

Reactive forms provide a model-driven approach to handling form inputs whose values change over the time. In Reactive forms, we need to import "ReactiveFormsModule" from angular forms library. we will use FormControl, FormGroup, FormArray, Validation classes with Reactive forms in angular 12 app.

If you have simple and basic form in your angular 12 application then i will prefer to use Reactive forms in angular. here i write simple example of Reactive forms with validation in angular 12.

You need to follow bellow step to create reactive forms in angular 12.

Step 1: Install Angular App

Here, in this step you need to create new ng app for this demo. if you have already created then don't create new angular 12 app.

ng new my-new-app

Step 2: Import FormsModule

If you want to create form in angular app then you need to import FormsModule from @angular/forms library. so let's add following code to app.module.ts file.

src/app/app.module.ts

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 { }

Step 3: Form with ngModel

In this step, we will write code of html form with ngModel. so add following code to app.component.html file.

I used bootstrap class on this form. if you want to add than then follow this link too: Install Boorstrap 5 to Angular 12.

src/app/app.component.html

<h1>Angular 12 Reactive Forms Validation Example - ItSolutionStuff.com</h1>

<form [formGroup]="form" (ngSubmit)="submit()">

<div class="form-group">

<label for="name">Name</label>

<input

formControlName="name"

id="name"

type="text"

class="form-control">

<div *ngIf="f.name.touched && f.name.invalid" class="alert alert-danger">

<div *ngIf="f.name.errors && f.name.errors.required">Name is required.</div>

<div *ngIf="f.name.errors && f.name.errors.minlength">Name should be 3 character.</div>

</div>

</div>

<div class="form-group">

<label for="email">Email</label>

<input

formControlName="email"

id="email"

type="text"

class="form-control">

<div *ngIf="f.email.touched && f.email.invalid" class="alert alert-danger">

<div *ngIf="f.email.errors && f.email.errors.required">Email is required.</div>

<div *ngIf="f.email.errors && f.email.errors.email">Please, enter valid email address.</div>

</div>

</div>

<div class="form-group">

<label for="body">Body</label>

<textarea

formControlName="body"

id="body"

type="text"

class="form-control">

</textarea>

<div *ngIf="f.body.touched && f.body.invalid" class="alert alert-danger">

<div *ngIf="f.body.errors && f.body.errors.required">Body is required.</div>

</div>

</div>

<button class="btn btn-primary" type="submit">Submit</button>

</form>

Step 4: updated Ts File

In ts file. we will write submit() and get all input fields values. so let's add following code to app.component.ts file.

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({

name: new FormControl('', [Validators.required, Validators.minLength(3)]),

email: new FormControl('', [Validators.required, Validators.email]),

body: new FormControl('', Validators.required)

});

get f(){

return this.form.controls;

}

submit(){

console.log(this.form.value);

}

}

Now you can run your application using following command:

ng serve

Output

{name: "Hardik Savani", email: "[email protected]", body: "This is a test"}

I hope it can help you...