validateInteger function

String? validateInteger(
  1. String? value, {
  2. required int min,
  3. int? max,
})

Implementation

String? validateInteger(String? value, {required int min, int? max}) {
  if (value == null || value.isEmpty) return 'Cannot be empty';

  int? intValue = int.tryParse(value);
  if (intValue == null) {
    return 'Must be a valid number';
  }

  if (intValue < min) {
    return 'Must be at least $min';
  }

  if (max != null && intValue > max) {
    return 'Must be at most $max';
  }

  return null;
}