https://github.com/facebook/react/tree/master/scripts/rollup https://github.com/ramda/ramda/blob/master/scripts/build

two options:

1. copy same folder structure
2. custom copy, folders do not matter

copy same

... .copy ha

custom copy

1. find
2. store metadata
3. transform - if function, use that, if string, if relative & isFilename, resolve filename else if relative else if absolute, use instead