This is great, thanks @gossi! I spent the last few days fighting with Istanbul and nyc trying to get all my paths to be the same and ultimately settled on just manually modifying them with sed. I think this might fix that issue?

Would it be possible to document a bit more about what projectRoot is or the use cases here? Like does projectRoot get prepended to the already determined paths? How is it different than passing cwd to the options etc

Thanks @RobbieTheWagner but I must confess, I only copy pasted things around to make my use-case work 🙈 In my project I was able to configure it for vitest, that worked and then I made it possible to have the same config for ember-cli-code-coverage, which then also made it work (I was happy to ignore how that worked and not question it). So the combo lcov + projectRoot is what people might likely be interested, so that's enough of a hint.

On the other hand it doesn't matter that much for that PR. Since this is very generic to have any options for any reporter. So it is up to consumers to figure out the options for each reporter.

Thanks @gossi! I still think it would be nice to have some more docs about this and when to use it etc. but I do want to go ahead and get it in to unlock this.

Just wanted to throw some thanks on this, I was searching for how to configure the projectRoot and am thrilled to see it's already here! 🤩