reset formarray angular 9 code example

Example 1: angular formarray remove all

const arr = new FormArray([
   new FormControl(),
   new FormControl()
]);
console.log(arr.length);  // 2

arr.clear();
console.log(arr.length);  // 0

Example 2: formarray set value at index

((this.form.get('controls') as FormArray).at(index) as FormGroup).get('description').patchValue(item.description);