unique method

JarArray<T> unique([
  1. String? message
])

Implementation

JarArray<T> unique([String? message]) {
  return addValidator((value) {
    if (value == null) return null;
    final set = Set<T>.from(value);
    return set.length == value.length
        ? null
        : (message ?? 'Elements must be unique');
  });
}