Node.js File System

Node.js File System Module (fs)

The fs module in Node.js facilitates interactions with the file system, allowing reading, writing, updating, deleting, and managing files and directories. It operates synchronously and asynchronously, giving developers flexibility based on the application’s needs.

Importing the fs Module

To utilize the file system module, it must first be imported using require:

const fs = require('fs');

This allows access to numerous built-in functions designed for handling files.

File Operations

Below the types of file operations :

1. Reading a File

The fs.readFile() method is employed to retrieve file contents asynchronously.

Syntax

fs.readFile(path, encoding, callback);

• path : The location of the file.
• encoding : The character encoding (e.g., utf8).
• callback : A function executed after reading, receiving an error and data parameter.

Example

fs.readFile('example.txt', 'utf8', (err, data) => {
    if (err) {
        console.error('Error reading file:', err);
        return;
    }
    console.log('File content:', data);
});

2. Writing to a File

To store data inside a file, fs.writeFile() is used asynchronously.

Syntax

fs.writeFile(path, data, encoding, callback);

• path : File location.
• data : Content to write.
• encoding : Optional encoding format.
• callback : Function executed upon completion.

Example

fs.writeFile('output.txt', 'Hello, Node.js!', 'utf8', (err) => {
    if (err) {
        console.error('Write operation failed:', err);
        return;
    }
    console.log('File saved successfully!');
});

3. Appending Data

fs.appendFile() allows appending new content to an existing file without overwriting.

Syntax

fs.appendFile(path, data, encoding, callback);

Example

fs.appendFile('log.txt', '\nNew entry added!', 'utf8', (err) => {
    if (err) throw err;
    console.log('Data appended!');
});

4. Deleting a File

To remove a file permanently, fs.unlink() is utilized.

Syntax

fs.unlink(path, callback);

Example

fs.unlink('obsolete.txt', (err) => {
    if (err) {
        console.error('File deletion error:', err);
        return;
    }
    console.log('File deleted successfully!');
});

5. Creating a Directory

The fs.mkdir() method is used to establish a new directory.

Syntax

fs.mkdir(path, options, callback);

Example

fs.mkdir('new_folder', { recursive: true }, (err) => {
    if (err) throw err;
    console.log('Directory created!');
});

6. Removing a Directory

For directory deletion, fs.rmdir() is effective.

Syntax

fs.rmdir(path, callback);

Example

fs.rmdir('old_folder', (err) => {
    if (err) throw err;
    console.log('Directory removed!');
});

Conclusion

The Node.js fs module provides comprehensive methods for handling files and directories. It supports both synchronous and asynchronous operations, empowering developers to manage file-based tasks efficiently while maintaining optimal performance.