Node.js File System (fs) Module Quiz Quiz

Challenge your understanding of the Node.js File System (fs) module, covering key methods, usage scenarios, and error handling. This quiz tests essential concepts and functions for working with files and directories in the Node.js environment.

1. Reading a File Synchronously

   Which fs module method should you use to read the entire contents of a file synchronously, returning its contents as a buffer?

   1. fs.readDirSync
   2. fs.readFileAsync
   3. fs.readSync
   4. fs.readFileSync

   Explanation: The fs.readFileSync method reads a file synchronously and returns its data as a buffer or string. fs.readFileAsync is not a valid method—it is a common typo for fs.readFile, which is asynchronous. fs.readDirSync is used for reading the contents of a directory, not a file. fs.readSync reads from a file descriptor and is typically used for lower-level operations.

2. Creating a Directory

   When you want to create a new directory, which fs module method supports creating nested directories in one call?

   1. fs.mkdir with { recursive: true } option
   2. fs.writeDir
   3. fs.createDirectory
   4. fs.mkdir without options

   Explanation: fs.mkdir with the { recursive: true } option allows you to create a directory and any necessary parent directories in one call. fs.createDirectory does not exist in the module and is an incorrect method name. fs.mkdir without options works only for single-level directories, and fs.writeDir is not a recognized method.

3. Handling Errors During File Reading

   Suppose you try to read a non-existent file using fs.readFile. What is the typical result?

   1. A warning is logged and the callback is not called
   2. An error object is passed to the callback as the first argument
   3. An empty string is returned to the callback
   4. The process exits immediately without warning

   Explanation: If fs.readFile fails to find the file, it passes an error object as the first argument to the callback, following standard error-first callback conventions. The process does not exit; this behavior allows you to handle errors gracefully. Returning an empty string would suggest the file exists and is empty, which is misleading. The callback is always called, and logging a warning is not the default behavior.

4. Watching File Changes

   Which fs module method allows you to monitor a file for changes such as modifications or renaming?

   1. fs.watchDir
   2. fs.observeFile
   3. fs.watch
   4. fs.monitor

   Explanation: fs.watch is the correct method for watching for changes to files or directories. fs.observeFile and fs.monitor are not actual fs module methods and are sometimes confused due to their descriptive names. fs.watchDir does not exist; directory watching is handled with fs.watch as well.

5. Deleting a File

   Which fs module method should you use to asynchronously delete a file?

   1. fs.unlink
   2. fs.removeFile
   3. fs.rmdir
   4. fs.deleteSync

   Explanation: fs.unlink is used to asynchronously delete a file. fs.removeFile is not a valid method and is easy to confuse due to its descriptive name. fs.deleteSync does not exist; the synchronous version is fs.unlinkSync. fs.rmdir is used to remove directories, not individual files.