putIfAbsent<T extends Object> method

T putIfAbsent<T extends Object>({
  1. Object? key,
  2. required T ifAbsent(),
})

根据Type + key获取，如果不存在则创建信息

Implementation

T putIfAbsent<T extends Object>(
    {Object? key, required T Function() ifAbsent}) {
  if (_isDestroyed) {
    throw Exception('extData has been destroyed.');
  }
  return _data.putIfAbsent(_genKey<T>(key: key), ifAbsent) as T;
}