oneOf function

ValidationRule oneOf(
  1. List<Object> values
)

The value must be one of the allowed values.

Implementation

ValidationRule oneOf(List<Object> values) => (String field, Object? value) {
      if (value == null) return null;
      return values.contains(value)
          ? null
          : '$field must be one of: ${values.join(', ')}';
    };