Node.js File System (fs Module) Operations Quiz Quiz

This quiz evaluates your fundamental knowledge of file system operations using the Node.js fs module, including reading, writing, and managing files and directories. Enhance your understanding of core Node.js fs methods, options, and behaviors for efficient file handling in JavaScript applications.

1. Reading text files with Node.js

   Which fs module method should you use to asynchronously read the contents of a text file as a string in Node.js?

   1. fs.readData
   2. fs.getFile
   3. fs.readText
   4. fs.readFile

   Explanation: The fs.readFile method is the correct choice to asynchronously read a file's contents in Node.js. fs.readData, fs.readText, and fs.getFile are not valid methods in the fs module; these options may look or sound similar, but do not exist. Only fs.readFile gives you access to file contents asynchronously.

2. Writing to a file

   If you need to overwrite the entire contents of a file with new data using Node.js, which method from the fs module should you call?

   1. fs.insertFile
   2. fs.writeFile
   3. fs.replaceFile
   4. fs.appendFile

   Explanation: fs.writeFile will completely overwrite the file with the new data or create it if it doesn't exist. fs.appendFile adds data to the end of the file, not overwriting existing content. fs.insertFile and fs.replaceFile are not valid methods in the module and would result in errors.

3. Checking if a file exists

   What is the recommended asynchronous method in fs module for checking if a file exists in recent versions of Node.js?

   1. fs.access
   2. fs.fileExists
   3. fs.pathCheck
   4. fs.exists

   Explanation: fs.access is the preferred method for checking file existence asynchronously and supports permission checks. fs.exists is deprecated and should not be used in new code. fs.fileExists and fs.pathCheck are not actual fs methods, and will cause errors if used.

4. Creating a new directory

   Which fs method will asynchronously create a new directory in the file system?

   1. fs.dirCreate
   2. fs.mkdir
   3. fs.createDir
   4. fs.makeDirectory

   Explanation: fs.mkdir is the correct asynchronous method for creating directories. fs.createDir, fs.makeDirectory, and fs.dirCreate are often misremembered but are not valid method names in the fs module.

5. Deleting files

   If you want to remove a file from the disk using Node.js, which fs method should you use?

   1. fs.erase
   2. fs.unlink
   3. fs.removeFile
   4. fs.delete

   Explanation: fs.unlink is used for deleting files in the fs module. fs.removeFile, fs.delete, and fs.erase may sound logical but are not the correct or valid method names for this task in Node.js.

6. Appending data to a file

   Which fs method should you choose to add new content to the end of an existing file without removing its current contents?

   1. fs.appendFile
   2. fs.extendFile
   3. fs.addData
   4. fs.writeMore

   Explanation: fs.appendFile correctly appends data to the end of a file, preserving the existing content. The other methods, fs.addData, fs.extendFile, and fs.writeMore, are invalid and do not exist in the module.

7. Synchronous vs asynchronous

   In Node.js, what is the primary difference between fs.readFile and fs.readFileSync?

   1. Both methods are synchronous.
   2. fs.readFileSync is asynchronous, fs.readFile is synchronous.
   3. fs.readFile is asynchronous, fs.readFileSync is synchronous.
   4. Both methods are asynchronous.

   Explanation: fs.readFile works asynchronously and does not block the event loop, while fs.readFileSync reads synchronously and blocks execution until complete. The reverse statement is incorrect, and the last two options are false since the methods have opposite behaviors.

8. Copying files

   Which fs method allows you to asynchronously copy a file from one location to another?

   1. fs.cloneFile
   2. fs.duplicate
   3. fs.copyFile
   4. fs.sendFile

   Explanation: fs.copyFile is the standard method for copying files in Node.js. The options fs.duplicate, fs.sendFile, and fs.cloneFile are not recognized methods in the fs module and will not work.

9. Reading directory contents

   If you need an array of all filenames inside a directory, which fs module method should you use in Node.js?

   1. fs.getFiles
   2. fs.dirContents
   3. fs.readList
   4. fs.readdir

   Explanation: fs.readdir returns an array of names found in the specified directory. fs.readList, fs.dirContents, and fs.getFiles are invalid method names and will produce errors if used.

10. Handling errors in fs operations

    When using fs methods with callbacks, how are errors typically reported to the developer?

    1. Thrown as exceptions automatically
    2. Displayed as console warnings only
    3. Returned as the last argument in the callback
    4. As the first argument in the callback

    Explanation: In the fs module, errors are conventionally passed as the first argument to the callback function. Exceptions are not automatically thrown for these asynchronous methods. Errors are not solely shown as warnings or returned as the last argument; those are misconceptions.