Broccoli (https://github.com/broccolijs/broccoli https://github.com/broccolijs/broccoli) has a really nice concept of "trees" that can be split or merged and co

Broccoli (https://github.com/broccolijs/broccoli https://github.com/broccolijs/broccoli) has a really nice concept of "trees" that can be split or merged and composed together.