integer static method

String? Function(String) integer({ String message = 'Please enter a valid integer.', int? min, int? max, })

Validates that the input is an integer.

Implementation

static String? Function(String) integer({
  String message = 'Please enter a valid integer.',
  int? min,
  int? max,
}) {
  return (value) {
    if (value.trim().isEmpty) return null;
    final num = int.tryParse(value);
    if (num == null) return message;
    if (min != null && num < min) return 'Value must be at least $min.';
    if (max != null && num > max) return 'Value must be at most $max.';
    return null;
  };
}