nonNegativeNumber static method

String? nonNegativeNumber(
  1. String? value
)

Validates non-negative number (>= 0)

Implementation

static String? nonNegativeNumber(String? value) {
  if (value == null || value.isEmpty) {
    return 'Ingresa un número';
  }

  final number = double.tryParse(value);
  if (number == null || number < 0) {
    return 'Debe ser un número no negativo';
  }

  return null;
}