Code Sharing between React and React Native

i am trying to find a good way to share codes between projects like Types and Redux Stores. The best 3 methods i've seen is:

1. Npm package - creating a private package.

• But if i wanted to change something in the npm package while developing, how would i do that?

2. Git Submodules

• I've seen that this way can have some side effects.

3. Copy/Paste

• The way i am doing now xD .. But really horrible way, cause i have to change the same stuff several times and can forget what i've changed..

How would u resolve this issue?