getStringValidator method

StringValueValidationFunction getStringValidator(Map spec)

Convenience method returning a generic validator for string input Widgets.

Implementation

StringValueValidationFunction getStringValidator(Map spec) {
  var required = parseBool(spec["required"]);
  final minLength = parseInt(spec["minLength"]);
  final maxLength = parseInt(spec["maxLength"]);
  if (minLength > 0) {
    required = true;
  }

  final requiredText = Lowder.properties.getText(
      spec["requiredMessage"] ?? "required_field_message", "errorMessage");
  final minLengthText = Lowder.properties.getText(
      spec["minLengthMessage"] ?? "_minimum_length_message_", "errorMessage",
      attributes: {"length": minLength});
  final maxLengthText = Lowder.properties.getText(
      spec["maxLengthMessage"] ?? minLength == maxLength
          ? "_exact_length_message_"
          : "_maximum_length_message_",
      "errorMessage",
      attributes: {"length": maxLength});

  final regex = spec["regex"] != null ? RegExp(spec["regex"]) : null;
  final regexMessage = Lowder.properties.getText(
      spec["regexMessage"] ?? "invalid_value_message", "errorMessage");

  return (value) {
    var valueLength = value?.length ?? 0;
    if (valueLength == 0) {
      if (required) return requiredText;
      return null;
    }
    if (valueLength < minLength) {
      if (minLength == maxLength) {
        return maxLengthText;
      }
      if (valueLength > 0) {
        return minLengthText;
      }
      return requiredText;
    }
    if (maxLength > 0 && valueLength > maxLength) {
      return maxLengthText;
    }
    if (value != null && regex != null && !regex.hasMatch(value)) {
      return regexMessage;
    }
    return null;
  };
}