Traverse a path and print directory tree

## Problem (Node.js) You are given an absolute or relative file-system path `rootPath`. Write a Node.js function/program that: 1. Validates that `rootPath` exists. 2. Reads the contents under `rootPath`. 3. Outputs a directory listing that includes both **files** and **subfolders**. ### Output format Choose one of the following and document it clearly in your answer: - A **tree** format (indented text), e.g. - `root/` - `a.txt` - `sub/` - `b.js` - Or a **structured JSON** representation, e.g. `{ name, type, children }`. ### Requirements / edge cases - If `rootPath` is a file, output just that file. - If `rootPath` is a directory, include all immediate children (optionally recursively—state which you implement). - Handle common errors (non-existent path, permission denied) gracefully. - If you sort entries, make the sort deterministic and specify it (e.g., folders first, then lexicographic by name).