I prefer modules, mostly because I work with Typescript a lot in which they're the default.

I've always found the .mjs extension a bit weird. It's essentially still the same JavaScript so I think the file should keep the .js extension. I'm not too sure if the mjs extension is even necessary anymore.

Edit: It seems like the mjs extension is still necessary if you don't specify type: "module" in your package.json.

https://nodejs.org/api/modules.html#the-mjs-extension

The reason I went with mjs is so that we don't need to specify "type": "module" in package.json. I don't like mjs either but I don't think there's another way to do it?

Yes, I agree. After all these are just a few build scripts so changing the whole projects module system wouldn't be a good idea.

Cool, I'll try to do the same changes in the bootstrap repo and then land this one :)

I'll revisit this when I'm done with the upstream changes so that we have the same point of reference.