How to remove all elements of a FormArray but one specific index?

Question

Is there any built-in functionality in Angular, so that I can say:

remove all FormArray elements except at index 2

maybe something like 'RemoveRange" as known from other libs?

Answer 1

Angular does not have this functionality inbuilt. You can instead store the required value, clear the formArray and then push the stored value back into the now empty formArray

keepOnly(index: number) {
  const valueToKeep = this.formArray.at(index);
  this.formArray.clear();
  this.formArray.push(valueToKeep);
}