Add charred json formatter module

[nikolap]

This PR adds charred as a JSON encode/decoder module for muuntaja, like cheshire.

The code comes from a private project that uses muuntaja + reitit.

Open to suggestions for how to test and build it locally in the context of this repo, as well as any change requests.

[mvarela]

Hi! This looks very good, but it'd need some tests. Would you be able to add those? You can see how the Cheshire integration is tested here https://github.com/metosin/muuntaja/blob/master/test/muuntaja/core_test.clj
For Charred, it'd be essentially the same tests needed.

[nikolap]

Thanks! Do you have any advice for how to run the project locally, i.e. dev setup? This is where I struggled to figure out how to add and run tests.

[mvarela]

You can try lein with-profile default,dev repl, which should get you an nREPL server with the dev profile loaded.

[nikolap]

Thanks, that helped me get started. Changes in last commit:

• Added charred tests
• Updated encoding handler for charred (default to encode-unicode false now, see opts in https://github.com/cnuernber/charred/blob/master/src/charred/api.clj#L708)
• Updated Contributing docs
• Add charred module to the scripts file
• Fix charred dep not loading properly

Let me know if anything else seems off!

[harold]

This is so great! I considered doing this (around the same time that you were actually just doing it, apparently).

With this I think we can perhaps remove cheshire + jsonista and other conflict ridden deps from some of our infrastructure pathways and for that I am grateful. Thanks all! 🙇