I love how clean this is -- could we get this working with ESM syntax though?

Good idea. We can use node -r esm

Done

Widening parenthesis as blocks eliminates the need for extra variables -- since this style is already heavily employed throughout Nuxt, can we also do it for things like this?

    for (const file of files) {
      copySync(
        resolve(source.options.rootDir, file),
        resolve(this.options.rootDir, file)
      )
    }

I've kept variables for reasons:

• No need to add extra comments. The code is much readable when using well-named variables
• Adding complexities (Like more logics for resolving path with some if conditions) would require fewer changes to the code
• Primarily I've separated variables soi can add some console logs about current operation without repeating code

@pi0 yup, I do that too. And fair enough. Usually though when I realize there are no further references to something, I edit it into the call in the final revision. Perhaps we can selectively do that when it makes sense just before merging.

Nice!

Could we leverage Map here? 🤔

Actually I wrote it with Map at the beginning, but object is handy and also map structure underlying,so I changed.