validateRequired method

String? validateRequired(
  1. String? input,
  2. String fieldName
)

Validates that a required field is not empty or null.

Returns an error message if the field is empty, otherwise null.

Implementation

///
  /// Returns an error message if the field is empty, otherwise null.
  String? validateRequired(String? input, String fieldName) {
    if (input == null || input.trim().isEmpty) {
      return '$fieldName is required.';
    }
    return null;
  }