requiredString static method

String Function(String?) requiredString(
  1. String message
)

Creates a validation rule that requires a non-empty string.

Returns message if the value is null or empty, otherwise returns an empty string.

Example:

Validations.requiredString('Name is required')

Implementation

static String Function(String?) requiredString(String message) {
  return (String? value) => (value?.isEmpty ?? true) ? message : '';
}