Node.js – File System Module (fs)

Node.js – File System Module (fs)

The File System (fs) module in Node.js allows you to interact with the file system on your computer. With fs, you can read, write, delete, update, rename, and stream files and directories using both synchronous and asynchronous methods.

Why Use the fs Module?

• Automate file and directory management.
• Build backend features like loggers, upload/download systems, and configuration loaders.
• Efficiently handle large files using streams.
• Work with both callback-based and promise-based APIs.

Importing the fs Module

You can also use the promise-based API:

1. Reading Files

Asynchronous Method:

Synchronous Method:

2. Writing Files

Asynchronous:

Synchronous:

writeFile() will overwrite the file if it exists.

3. Appending Data to a File

4. Renaming Files

5. Deleting Files

6. Creating a Directory

7. Reading Contents of a Directory

8. File Stats and Metadata

9. Using Streams (for Large Files)

Reading a file with stream:

Writing to a file with stream:

10. Using fs.promises for Modern Async/Await

Key Takeaways

• The fs module is used to perform file and directory operations.
• Provides both synchronous and asynchronous (non-blocking) methods.
• Use streams for large file operations.
• Use fs.promises with async/await for cleaner, modern code.
• Always handle errors in file operations to avoid crashes.