ReactiveForm

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 11 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 { }
Read Also: Angular Get Parameters from URL Route
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 4 to Angular 11.

src/app/app.component.html

<h1>Angular 11 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.required">Name is required.</div>
            <div *ngIf="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.required">Email is required.</div>
            <div *ngIf="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.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