For version 4 I needed to install under automation JS. I normally use addons.cfg for this but can’t find how and where to add this.
I tried 2 options but none of them is working
transformation = js
transformation = openhab-js
Same place as it always was, under $OH_CONFIG/services/addons.cfg.
There is no longer any language based transformations. There is one built in SCRIPT transform that doesn’t need to be installed that will work with any installed rules language including Rules DSL.
So you’ll need to add this to some other line in addons.cfg. What line that is 
, I don’t mess with text file configs (because I don’t like fighting problems like this). I’d guess it would go on an automation line since that’s the category for rules language add-ons.
As for the ID of the add-on, well you can find that the same way it’s always been found. Go to the add-on docs and the last part of the URL is the ID.
https://www.openhab.org/addons/automation/jsscripting/
-----------
Or you can pull the JSON for all add-ons from the REST API and search for the ID there.