You have to create another widget since the Web widget is based on React, and the Native widget is based on React-native.
The javascript logic can be the same (so re-used), but the big difference is the rendering. React-native doesn’t understand html elements (div,article,...). React-native uses the elements View, Text,…
Also a big difference is the styling. In web you can use CSS or SASS but in native you can only use javascript styled objects.