nextKey method

Object? nextKey(
  1. Object? key
)

Implementation

Object? nextKey(Object? key) {
  if (keys == null || (key == null && changed)) {
    initKeys();
    changed = false;
  }

  Object? nextKey = keys![key];
  if (nextKey == null && key != null && key != lastKey) {
    throw Exception("invalid key to 'next'");
  }

  return nextKey;
}