How to share/organize common logic for ssr and client side code

[karanpvyas]

I have a use case where I need to make authenticated calls to my backend to serve data.

This means -
i) I'd need to run some logic for building my request
ii) Attach the necessary auth headers which I'd get in a cookie from the browser - before I make a call within getServerSideProps
iii) Be able to do/use the same code for making calls (e.g. pagination on scroll) when inside client/browser now.

P.S. There are several calls - bootup/data-fetch etc which need to be made when gettingServerSideProps.

I am wondering what's the best way to do so when SSRing

Also P.S. -> Uptil now when I didn't do any SSR, I had several global variables/configs available in my React context on the browser side, using which I could "make" my request's payload and then do the n/w calls.
Now within getServerSideProps -> I no more have React Context of any sort, and need to pass on my configs/global variables all the way down to all function calls :(

Any help/insight would be appreciated, thanks you!