Function minLengthValidator

packages/forms/src/validators.ts:533–546

(minLength: number)

 * For example, the object {id: 1, length: 0, width: 0} should be validated.
 */
export function minLengthValidator(minLength: number): ValidatorFn {
  return (control: AbstractControl): ValidationErrors | null => {
    const length = control.value?.length ?? lengthOrSize(control.value);
    if (length === null || length === 0) {
      // don't validate empty values to allow optional controls
      // don't validate values without `length` or `size` property
      return null;
    }

    return length < minLength
      ? {'minlength': {'requiredLength': minLength, 'actualLength': length}}
      : null;
  };
}

/**
 * Validator that requires the number of items in the control's value to be less than or equal