Angular 2: Accessing data from FormArray

Question

I have prepared a from using ReactiveForms provided by angular2/forms. This form has a form array products:

this.checkoutFormGroup = this.fb.group({
                     


        

Answer 1

While casting the AbstractControl to a FormArray before using the at() method is a way of doing it, I haven't seen anybody pointing out that you can also do it using the get() method, which requires no casting.

According to Angular's Documentation, the signature of get() is :
get(path: string | (string | number)[]): AbstractControl | null

Which means you can also access FormArray's controls with it.

Example :

const formGroup = new FormGroup({
  list: new FormArray([
    new FormControl('first'),
    new FormControl('second'),
  ]),
});

const firstValue = formGroup.get('list.0').value; // Returns 'first'
const secondValue = formGroup.get('list.1').value; // Returns 'second'

This is really useful, when you want to bind a FormControl in the HTML, where you can't cast anything :

---

Here is a summary of ways of doing it :

const firstControl = listControl.get('list.0');

const firstControl = listControl.get(['list', 0]);

const firstControl = listControl.get('list').get('0'); // You need a string and not a number

const listControl = formGroup.get('list') as FormArray;
const firstControl = listControl.at(0);