How to create empty formarray

Question

I would like to create an empty formarray so i will be able to push elements later.

i know that i can do something like this using "criterias.controls.length = 0;" after declaring the FormArray but i'm looking for a way to create the formArray with 0 length in the as part of the declaration.

criterias = new FormArray([]);
criterias.controls.length = 0;
values.forEach(item => {
    criterias.controls.push(new FormGroup({
      'type': new FormControl(item.type, Validators.required),
      'criteria': new FormControl(item.criteria, Validators.required)
    }));
  });

Ricardo · Accepted Answer · 2018-02-26 16:20:55Z

12

you can use the form builder class to help you create the reactive form

    this.baseForm = this.fb.group({
        criterias: this.fb.array([])
    })

also is good if you have a method that returns you form array

get criterias(): FormArray {
    return this.baseForm.get("criterias") as FormArray
}

base on that you can create a add method an a remove method

  addCriteria() {
    this.criterias.push(this.fb.group({

     }))
  }

  removeCriteria(index) {
      this.criterias.removeAt(index)
  }

answered Feb 26, 2018 at 16:20

Ricardo

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1 Comment

Omtechguy Over a year ago

Thank you very much @Ricardo, I think that this.fb.array([]) will create an array with one element and not empty one (Zero length).

HannaAB · Accepted Answer · 2023-01-23 19:33:19Z

0

you can write it this way:

let criterias !: FormArray;

and then push the FormGroup ...

answered Jan 23, 2023 at 19:33

HannaAB

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