Angular 10 Reactive Forms FormArray Example

This post is focused on angular 10 reactive forms formarray example. this example will help you angular 10 formarray example. if you want to see example of angular 10 formarray reactive forms then you are a right place. i would like to share with you angular 10 reactive formarray validation. You just need to some step to done formarray in angular 10 example.

I will show you very simple and step by step example of how to use formarray in angular 6, anuglar 7, angular 8, angular 10 and angular 10 application.

Using FormArray you can create building blocks of forms with FormControl in Angular. FormArray will key values of each child FormControl into an array. You can easily create dynamic add more input fields example using FormArray in Angular.

FormArray Constructor:

constructor(controls: AbstractControl[], validatorOrOpts?: ValidatorFn |
 AbstractControlOptions | ValidatorFn[], asyncValidator?: AsyncValidatorFn | 
 AsyncValidatorFn[])

In this example we will create form with product name and user can add multiple quantity with price. we will use formgroup and formarray to create dynamic form in angular application.

You can see bellow layout for demo. let's follow bellow step.

Import FormsModule:

src/app/app.module.ts

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { FormsModule, ReactiveFormsModule } from '@angular/forms';
   
import { AppComponent } from './app.component';
   
@NgModule({
  imports:      [ BrowserModule, FormsModule, ReactiveFormsModule ],
  declarations: [ AppComponent ],
  bootstrap:    [ AppComponent ]
})
export class AppModule { }

updated Ts File

In this file we will first import FormGroup, FormControl,FormArray and FormBuilder from angular forms library.

src/app/app.component.ts

import { Component } from '@angular/core';
import { FormGroup, FormControl, FormArray, FormBuilder } from '@angular/forms'
  
@Component({
  selector: 'my-app',
  templateUrl: './app.component.html',
  styleUrls: [ './app.component.css' ]
})
export class AppComponent  {
  name = 'Angular';
  
  productForm: FormGroup;
   
  constructor(private fb:FormBuilder) {
   
    this.productForm = this.fb.group({
      name: '',
      quantities: this.fb.array([]) ,
    });
  }
  
  quantities() : FormArray {
    return this.productForm.get("quantities") as FormArray
  }
   
  newQuantity(): FormGroup {
    return this.fb.group({
      qty: '',
      price: '',
    })
  }
   
  addQuantity() {
    this.quantities().push(this.newQuantity());
  }
   
  removeQuantity(i:number) {
    this.quantities().removeAt(i);
  }
   
  onSubmit() {
    console.log(this.productForm.value);
  }
}

Template Code:

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 10.

src/app/app.component.html

<div class="container">
  
  <h1>Angular FormArray Example - ItSolutionStuff.com</h1>
  
  <form [formGroup]="productForm" (ngSubmit)="onSubmit()">
    
    <p>
      <label for="name">Product Name:</label>
      <input type="text" id="name" name="name" formControlName="name" class="form-control">
    </p>
  
    <table class="table table-bordered" formArrayName="quantities">
      <tr>
        <th colspan="2">Add Multiple Quantity:</th>
        <th width="150px"><button type="button" (click)="addQuantity()" class="btn btn-primary">Add More</button></th>
      </tr>
      <tr *ngFor="let quantity of quantities().controls; let i=index" [formGroupName]="i">
        <td>
            Quantity :
            <input type="text" formControlName="qty" class="form-control">
        </td>
        <td>
            Price:
            <input type="text" formControlName="price" class="form-control">
        </td>
        <td>
            <button (click)="removeQuantity(i)" class="btn btn-danger">Remove</button>
        </td>
      </tr>
    </table>
   
    <button type="submit" class="btn btn-success">Submit</button>
    
  </form>
    
  <br/>
  {{this.productForm.value | json}}
</div>

Now you can run your application using following command:

ng serve

I hope it can help you...