Reactive forms in Angular

Sure, reactive forms in Angular provide a more explicit and robust approach to handling form inputs compared to template-driven forms. They're built around the use of FormControl, FormGroup, and FormArray instances that are created and manipulated in the component class.

Here's a basic rundown of how reactive forms work in Angular:

  1. Import necessary modules:

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

  2. Create a FormGroup and FormControls:

                        // Inside your component class
                        myForm: FormGroup;
                        constructor(private formBuilder: FormBuilder) {
                          this.myForm ={
                            // Define form controls with initial values and validators
                            firstName: ['', Validators.required],
                            lastName: ['', Validators.required],
                            email: ['', [Validators.required,]],
                            //...other form fields

  3. Link form controls to HTML:

                        <form [formGroup]="myForm" (ngSubmit)="onSubmit()">
                            <input type="text" formControlName="firstName">
                            <input type="text" formControlName="lastName">
                            <input type="email" formControlName="email">
                            <!-- ...other form fields -->
                            <button type="submit">Submit</button>

  4. Reacting to changes and form submission:

                        // Inside your component class
                        onSubmit() {
                          if (this.myForm.valid) {
                            // Handle valid form submission
                            const formData = this.myForm.value;
                            // something with formData
                          } else {
                            // Handle invalid form
                            // Display errors, mark fields as touched, etc.

Additional Functionality:

  • Validators: Use built-in or custom validators to validate form inputs.
  • FormArray: For dynamic form controls like lists.
  • Dynamic Form Controls: Add or remove form controls dynamically based on user actions.

Reactive forms offer greater flexibility and testability, especially for complex forms and dynamic form control scenarios in Angular applications.

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