validator static method

String? Function(String?) validator(List<RegexModel> rules, { bool optional = false, })

A TextFormField.validator that returns the first unmet rule's title, so Form.validate() checks the same rules as the checklist. Empty is "Required", or fine when optional.

Implementation

static String? Function(String?) validator(
  List<RegexModel> rules, {
  bool optional = false,
}) => (value) {
  if ((value ?? '').isEmpty) {
    return optional ? null : RegexLabels.current.required;
  }
  for (final rule in rules) {
    if (!rule.matches(value!)) return rule.title;
  }
  return null;
};