File Explorer

This web-based file explorer app was built using TypeScript, Next.js, and the MUI 5 Tree View component.

Author: Abraham Lopez (ablopez824@gmail.com)

Requirements

You only need Node.js version 14 or greater (may work on slightly older versions) to be installed in your system.

Getting Started

1. First run npm install to install all the required dependencies.

2. To run in development mode use the following command (be sure to not miss the . dot in the middle) and replace /path/to/folder with the absolute or relative path to the folder you want to explore (e.g. use ~/ if you want to explore your user folder in a Linux/Mac environment):

npm run dev . /path/to/folder

Tip: Be sure to put your folder path between double quotes if the path contains spaces.

As a quick test, you can explore the files and folders of this project by running the following command (be sure to include the slash at the end, otherwise the pointer to the current path will be ignored):

npm run dev . ./

If you want to explore multiple folders just separate them with spaces, for example:

npm run dev . "/path/to/folder1" "/path/to/folder2" "/path/to/folder3"

3. Then, open http://localhost:3000 in your web browser to use the file explorer for this folder(s).

Run in Production

To run the file explorer in production mode please execute npm run build first and then use npm start instead of npm run dev as described in the previous section.

Example:

npm run build
npm start . /path/to/folder

Technical Notes

Performance Design Choices

• When the file explorer is first opened only the first level of the directory tree is loaded, while the subfolders are lazy-loaded until they're opened by the user. When a given folder in the tree view is collapsed by the user it is automatically unmounted which allows to keep the DOM as small as possible when expanding multiple folders over time.

• The file explorer component uses a recursive component tree of smaller individual tree view components which only track the first level of a single folder each one, which keeps the UI responsive by saving React from having to do a full reconciliation/diffing and re-rendering of the whole directory tree whenever the state (which contains the currently loaded file/folder structures) is updated, which is specially useful when dealing with large directory trees.

• To allow the file explorer to automatically reflect changes in the files and folders that it has loaded, a simple timer-based polling approach was chosen to frequently reload the entries of the currently opened (expanded) folders in the tree view every couple of seconds (configurable in the code of the PathExplorerTreeView component). When a folder is closed (collapsed) in the tree view, the timer is automatically destroyed in order to reduce the extent of polling to the minimum possible.

Project Structure

• pages/: Contains the code for the user interface views (except for the api/ subfolder, see below, follows Next.js's default project structure).
  • pages/_app.tsx: Entrypoint for application. Loads pages/index.tsx as default view.
• pages/api/: Contains the code for the backend API endpoints that power the UI. Uses Next.js's file-system-based routing (just like with the UI views).
• styles/: Contains the styles for the UI views. They're automatically namespaced by taking advantage of Next.js's support for CSS modules, so we don't have to worry about style collisions.
• public/: Contains UI assets (e.g. images, icons, etc.) - not used currently
• lib/: Contains local helper functions.