Pinch-to-zoom tree navigation

Pinch outward on a folder to expand deeper. Pinch inward to collapse the subtree under the pointer until the branch folds shut.
Or hold Cmd/Ctrl and scroll

This is a UX concept demo, and source code is not provided because the implementation details depend on your technology stack.
You are welcome to build on the idea, adapt it, and share your own implementation

Check other projects at delopsu.com