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Add / Remove Multiple Input Fields Dynamically using Form Array in Angular Reactive Forms





Dynamically Create multiple input fields using angular

Using Angular Reactive Forms FormArray, we can easily add/remove multiple input fields (FormControl) or group of input fields (FormGroup) in a form.
In this tutorial, I will teach you how to create a group of addresses with both add and remove functionality using Angular Reactive Forms FormArray.




  • dynamically create multiple inputs using angular


Steps to Create Dynamic Input Fields in Angular Reactive Forms

  • Import ReactiveFormsModule in your module
  • Declare a property called addressForm which is our FormGroup
  • Declare a property called addresses which is our FormArray
  • Use the FormBuilder Service to create our FormGroup model.
  • Write three methods addAddress , removeAddress, createAddress

Import ReactiveFormsModule

In order to use FormGroup, FormArray and FormControl we should import ReactiveFormsModule in our module (app.module.ts).
import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';

import { ReactiveFormsModule } from '@angular/forms';

@NgModule({
  imports: [
    BrowserModule,
    ReactiveFormsModule // import reactive forms module
  ]
});

Create FormGroup using Form Builder

Create a property called addressForm (whatever name you like) in your component.ts. Inject the FormBuilder service in your constructor.
FormBuilder is an angular service used to create FormGroups, FormControls, and FormArrays easily. By using FormBuilder.array method, you can create FormArray.

You may pass a function into the FormBuilder.array method to set the default value for it. The function should either return a FormControl or FormGroup.
In our case, we pass createAddress() inside the array method, by default a single address group will be created.
public addressForm: FormGroup;
  
constructor(private fb: FormBuilder) {
  this.addressForm = this.fb.group({
     addresses: this.fb.array([ this.createAddress() ])
  });
}

 createAddress(): FormGroup {
    return this.fb.group({
      address: '',
      street: '',
      city: '',
      country: ''
    });
 }

Dynamic FormGroups/FormControls in Component Template using FormArray

Create a form element and assign the addressForm as it’s formGroup
<form [formGroup]="addressForm" class="container mt-3">
   <!-- code form form array here -->
</form>

Add FormGroup/FormControls Dynamically in Angular Reactive Forms:

Create a button in your component.html, on its click invoke addAddress function as follows
<button type="button" class="btn btn-primary mb-2" (click)="addAddress()">Add Address</button>
In addAddress function, you should get the addresses formArray by accessing the get method of the FromGroup. Push the new FormGroup into the addresses formArray by invoking the createAddress function.
addAddress(): void {
    this.addresses = this.addressForm.get('addresses') as FormArray;
    this.addresses.push(this.createAddress());
}

List the Dynamically Created FormGroup using FormArray

In your component.html, you should loop over the FormArray using *ngFor directive. Create a getter to access the controls of the FormArray
// component.ts
get addressControls() {
  return this.addressForm.get('addresses')['controls'];
}
Loop over the form controls of FormArray, declare a local variable in the *ngFor to store the index in *ngFor=let address of addressControls; let i = index;
Assign the i to formGroupName dynamically, then create the necessary input fields and set the formControlName for it.
<section class="container border mb-4 p-3" formArrayName="addresses" 
        *ngFor="let address of addressControls; let i = index;">
        <div [formGroupName]="i">
          <div class="row">
            <div class="col-6">
                <h4>Address {{i + 1}}</h4>
            </div>
            <div class="col-6 text-right">
                <button type="button" class="btn btn-danger btn-sm" (click)="removeAddress(i)">Remove</button>
            </div>
          </div>
          <div class="row">
            <div class="col-6">
                <div class="form-group">
                    <label>Address</label>
                    <input type="text" class="form-control" formControlName="address" placeholder="St. Thomas Apartment"/>
                  </div>
            </div>
            <div class="col-6">
                <div class="form-group">
                    <label>Street</label>
                    <input type="text" class="form-control" formControlName="street" placeholder="South Street"/>
                  </div>
            </div>
          </div>
          
          <div class="row">
            <div class="col-6">
                <div class="form-group">
                    <label>City</label>
                    <input type="text" class="form-control" formControlName="city" placeholder="Mumbai"/>
                  </div>
            </div>
            <div class="col-6">
                <div class="form-group">
                    <label>Country</label>
                    <select class="form-control" formControlName="country" placeholder="India">
                      <option value="india">India</option>
                      <option value="usa">USA</option>
                      <option value="england">England</option>
                    </select>
                  </div>
            </div>
          </div>
        </div>
    
      </section>

Remove FormGroup/FormControl from FormArray in Angular Reactive Forms

Create a remove button inside the formGroupName div, on its click, invoke a method called removeAddress with the current index i.
<button type="button" class="btn btn-danger btn-sm" (click)="removeAddress(i)">Remove</button>
Inside your component.ts, create a method called removeAddress which will remove the form group from the form array using removeAt method.
removeAddress(i: number) {
   this.addresses.removeAt(i);
}

Conclusion:

I hope, This angular reactive forms tutorial helps you to understand how to add and remove multiple form controls or form groups using FormArray. If you have any doubts about implementing dynamic forms using the angular reactive forms module, make a comment below.

full code 


app.component.html
<form [formGroup]="addressForm" class="container mt-3" (ngSubmit)="logValue()">
  <div class="row justify-content-center">
    <div class="col-6">
        <button type="button" class="btn btn-primary mb-2" (click)="addAddress()">Add Address</button>
      <section class="container border mb-4 p-3" formArrayName="addresses" 
        *ngFor="let address of addressControls; let i = index;">
        <div [formGroupName]="i">
          <div class="row">
            <div class="col-6">
                <h4>Address {{i + 1}}</h4>
            </div>
            <div class="col-6 text-right">
                <button type="button" class="btn btn-danger btn-sm" (click)="removeAddress(i)">Remove</button>
            </div>
          </div>
          <div class="row">
            <div class="col-6">
                <div class="form-group">
                    <label>Address</label>
                    <input type="text" class="form-control" formControlName="address" placeholder="St. Thomas Apartment"/>
                  </div>
            </div>
            <div class="col-6">
                <div class="form-group">
                    <label>Street</label>
                    <input type="text" class="form-control" formControlName="street" placeholder="South Street"/>
                  </div>
            </div>
          </div>
          
          <div class="row">
            <div class="col-6">
                <div class="form-group">
                    <label>City</label>
                    <input type="text" class="form-control" formControlName="city" placeholder="Mumbai"/>
                  </div>
            </div>
            <div class="col-6">
                <div class="form-group">
                    <label>Country</label>
                    <select class="form-control" formControlName="country" placeholder="India">
                      <option value="india">India</option>
                      <option value="usa">USA</option>
                      <option value="england">England</option>
                    </select>
                  </div>
            </div>
          </div>
        </div>
    
      </section>

      <div class="text-right">
          <input type="submit" class="btn btn-success" value="Submit"/>
      </div>
      
    </div>
  </div>

</form>
/// app.component.ts
import { Component } from '@angular/core';
import { FormBuilder, FormGroup, FormArray } from '@angular/forms';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.scss']
})
export class AppComponent {
  public addresses: FormArray;
  public addressForm: FormGroup;
  constructor(private fb: FormBuilder) {
    this.addressForm = this.fb.group({
      addresses: this.fb.array([ this.createAddress() ])
    });
  }

  ngOnInit() {

  }

  get addressControls() {
    return this.addressForm.get('addresses')['controls'];
  }

  createAddress(): FormGroup {
    return this.fb.group({
      address: '',
      street: '',
      city: '',
      country: ''
    });
  }

  addAddress(): void {
    this.addresses = this.addressForm.get('addresses') as FormArray;
    this.addresses.push(this.createAddress());
  }

  removeAddress(i: number) {
    this.addresses.removeAt(i);
  }

  logValue() {
    console.log(this.addresses.value);
  }
}
// app.component.scss$color-primary: rgba(67,66,93,255);
$color-text: #43425d;
$color-text-lite: rgba(#4d4f5c,.5);

.login-container {
    font-family: "Source Sans Pro";
    .sidebar {
        background-image: url(/assets/images/group_4.png), linear-gradient(-136.82353093203deg , rgba(36,35,72,255) 0%, rgba(90,85,170,255) 100%);
        background-size: cover;
        min-height: 100vh;
    }

    .title, a {
        color: $color-text;
    }

    .title {
        font-weight: bold;
        letter-spacing: 5px;
    }

    .tag {
        color: $color-text-lite
    }

    .btn-main {
        background: $color-primary;
    }

    .btn-main-outline {
        border: 1px solid $color-primary
    }

}
//app.module.ts
import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';

import { AppRoutingModule } from './app-routing.module';
import { AppComponent } from './app.component';
import { BrowserAnimationsModule } from '@angular/platform-browser/animations';
import { ReactiveFormsModule } from '@angular/forms';

@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule,
    ReactiveFormsModule,
    AppRoutingModule,
    BrowserAnimationsModule,
  ],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule { }

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