Deal with shared files... make library or package?

Our company has a couple of apps. What we do is brand the same app for other companies. (Different logo, colors and so forth).

We have our pages, and files and all that stuff that need to be used by multiple apps so the only thing that changes is the style.
The problem is, Angular 2+ and Iconic seem really bad at sharing files. You setup an app, you have one entry point to that app.

We are trying to figure out how to solve this problem. We thought of using symbolic links in Linux, and a proof of concept worked, we have one new guy that wants to use Windows. I don’t think those symbolic links will work.

This new guy is suggesting using Git to control this. It seems like it can be done, but I find it confusing, and feel like it will be hard to maintain down the road.

The last suggestion was make some npm (or maybe) npm package, or some Angular library or something. Haven’t looked must into those? We don’t want to push the files up to npm. Building some node_module I guess for most of our files. Then any app could reference them?

Any body else have this problem? Or a solution?

Maybe you can create a custom hook that changes the required files for the build (Company logo and so on from a json file ith the data that changes)

Otherwise the Git approach isn’t that bad, you would have a main branch with the main app and branches for each companie with only the files changed that needed to be changed.
And with git you have also the backup if sth. goes wrong.

You may find some idea in the following recent thread: Share modules between apps - architecture