Stable Class
What it does
This is the base class for FormControl, FormGroup, and FormArray. It provides some of the shared behavior that all controls and groups of controls have, like running validators, calculating status, and resetting state. It also defines the properties that are shared between all sub-classes, like value, valid, and dirty. It shouldn't be instantiated directly.
Class Overview
class AbstractControl {
constructor(validator: ValidatorFn, asyncValidator: AsyncValidatorF