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Traverse a path and print directory tree

AdobeSoftware Engineer · Technical Screen
MediumSoftware EngineerTechnical ScreenCoding & Algorithms

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This problem tests your ability to recursively traverse a directory structure and format the output into a human-readable, indented tree structure while handling potential I/O errors.

Problem Statement

Given a root directory path, implement a function printDirectoryTree(rootPath) that traverses the filesystem and prints a hierarchical tree structure to the console. The output should visually represent the nesting levels using indentation and prefixes.

Requirements

  1. For each directory, list its contents sorted alphabetically.
  2. Use a tree-like visual format. For example: 
    root/
├── config.json
├── src/
│   ├── index.js
│   └── utils.js
└── README.md
  3. If a directory cannot be accessed (e.g., permission denied), skip it and continue processing.
  4. Your solution should use synchronous filesystem methods (e.g., fs.readdirSync, fs.statSync) for simplicity.

Function Signature

function printDirectoryTree(rootPath, prefix = '') {
  // Implementation here
}

Constraints

  • Handle deep directory structures without overflowing the stack (though you may assume reasonable depth).
  • Ignore hidden files (files starting with a dot .).
  • The input rootPath is guaranteed to be a string representing a valid starting directory.

Edge Cases

  • Empty directories.
  • Symlinks (you can choose to treat them as files or skip them).
  • Directories with restricted permissions.

Hints

Hint 1

Use 'fs.readdirSync' with the 'withFileTypes' option set to 'true' to easily distinguish between files and directories.

Hint 2

Maintain a 'prefix' string parameter that grows as you recurse deeper into subdirectories to handle the visual indentation.

Hint 3

Sort the results of 'readdirSync' alphabetically before iterating through them to ensure the output is deterministic.

Follow-up questions

  • How would you modify your implementation to output the result as a nested JSON object instead of a printed tree?
  • If the directory tree is extremely large, how would you change your approach to avoid blocking the main event loop in Node.js?
  • How would you handle circular symlink references to prevent an infinite recursion loop?