How to Build Dynamic Form Controls with Angular Reactive Forms

Angular Reactive Forms provide a powerful and flexible way to build dynamic form controls. With reactive forms, you can create forms that change and respond to user input, making for a more interactive and user-friendly experience.

Getting Started

To get started with Angular Reactive Forms, you’ll need to have a basic understanding of HTML, CSS, and JavaScript. You’ll also need to have Angular installed on your machine. If you haven’t already installed Angular, you can do so by running the following command in your terminal:

    
      npm install -g @angular/cli
    
  

Once you have Angular installed, you can create a new project using the following command:

    
      ng new my-app
    
  

Creating Dynamic Form Controls

With Angular Reactive Forms, you can easily create dynamic form controls that change based on user input. To do this, you’ll need to use the FormBuilder service to create a form group, and the FormArray class to create dynamic form controls.

Here’s an example of how you can create a dynamic form control that allows users to add and remove input fields:

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

      @Component({
        selector: 'app-dynamic-form',
        templateUrl: './dynamic-form.component.html'
      })
      export class DynamicFormComponent {
        form: FormGroup;

        constructor(private fb: FormBuilder) {
          this.form = this.fb.group({
            dynamicInputs: this.fb.array([])
          });
        }

        get dynamicInputs() {
          return this.form.get('dynamicInputs') as FormArray;
        }

        addInput() {
          this.dynamicInputs.push(this.fb.control(''));
        }

        removeInput(index: number) {
          this.dynamicInputs.removeAt(index);
        }
      }
    
  

In the example above, we’re creating a dynamicInputs FormArray and using the addInput and removeInput methods to add and remove input fields from the form.

Using Dynamic Form Controls in the Template

Once you’ve created the dynamic form controls in your component, you can use them in your template by using the formControlName directive. Here’s an example of how you can use the dynamic form controls in your template:

    
      

        

          

            
            Remove
          
        
        Add Input
      
    
  

In the example above, we’re using the ngFor directive to loop through the dynamicInputs controls and create an input field and a remove button for each control. We’re also using the addInput method to add new input fields to the form.

Conclusion

With Angular Reactive Forms, you can easily create dynamic form controls that change and respond to user input. By using the FormBuilder service and the FormArray class, you can build forms that provide a more interactive and user-friendly experience for your users.