Function validator

packages/forms/src/model/abstract_model.ts:584–586

* Returns the function that is used to determine the validity of this control synchronously. * If multiple validators have been added, this will be a single composed function. * See `Validators.compose()` for additional information.

()

   * See `Validators.compose()` for additional information.
   */
  get validator(): ValidatorFn | null {
    return this._composedValidatorFn;
  }
  set validator(validatorFn: ValidatorFn | null) {
    this._rawValidators = this._composedValidatorFn = validatorFn;
    this._updateHasRequiredValidator();