Converting webpack to Node project – where to put package.json files to load modules

I unpacked the following webpack using the source-map-unpacker project:
https://assets2.dutchie.com/main-b32e99adfce6c95e05dd.bundle.js

I posted the unpacked code to GitHub:
https://github.com/summersab/dutchie-taxes

The file index.js at the root is the only file I created and shows what I am trying to do. I need to access the functions in the module shared/helpers/taxes.js. However, I am not a Node programmer, so I am having trouble figuring out how to get the code to run, where to put package.json files so modules are recognized, etc. Could someone give me a hand?