Performing File and Directory Operations in Node.js

1. Introduction

In this tutorial, we're going to explore how to perform file and directory operations in Node.js. You will learn how to create, read, update, and delete files and directories using the built-in fs (file system) module in Node.js.

By the end of this tutorial, you should be able to:

• Understand how to manipulate files and directories in Node.js
• Apply these operations in your web development projects

Prerequisites: Basic knowledge of JavaScript and Node.js is required. You should also have Node.js installed on your system.

2. Step-by-Step Guide

Node.js fs module provides an API to interact with the file system in a manner closely modeled around standard POSIX functions.

To use this module, you need to require it in your script:

const fs = require('fs');

Creating a New File

To create a new file in Node.js, you can use the fs.writeFile() method:

fs.writeFile('test.txt', 'Hello, World!', (err) => {
  if (err) throw err;
  console.log('File has been created');
});

Reading a File

To read a file in Node.js, you can use the fs.readFile() method:

fs.readFile('test.txt', 'utf8', (err, data) => {
  if (err) throw err;
  console.log(data);
});

3. Code Examples

Let's put everything together and create a more complex example:

// Include fs module
const fs = require('fs');

// Use fs.writeFile() method to create a new file
fs.writeFile('test.txt', 'Hello, World!', (err) => {
  if (err) throw err;

  console.log('File has been created');

  // Use fs.readFile() method to read the file
  fs.readFile('test.txt', 'utf8', (err, data) => {
    if (err) throw err;

    console.log(data);
  });
});

In this code snippet:

1. We first include the fs module.
2. We use fs.writeFile() to create a new file 'test.txt' and write 'Hello, World!' to it. If the file already exists, it will be overwritten.
3. In the callback function of fs.writeFile(), we use fs.readFile() to read the file we just created. The content of the file will be printed to the console.

4. Summary

In this tutorial, we've covered the basics of performing file and directory operations in Node.js. We've learned how to create a new file and how to read a file using the fs module. The next step would be to explore other methods provided by the fs module, such as fs.appendFile(), fs.unlink(), and fs.mkdir().

5. Practice Exercises

1. Write a script to append text to an existing file.
2. Write a script to delete a file.
3. Write a script to create a new directory.

Exercise 1 Solution:

fs.appendFile('test.txt', ' This is a test.', (err) => {
  if (err) throw err;
  console.log('Text has been appended');
});

Exercise 2 Solution:

fs.unlink('test.txt', (err) => {
  if (err) throw err;
  console.log('File has been deleted');
});

Exercise 3 Solution:

fs.mkdir('testDir', (err) => {
  if (err) throw err;
  console.log('Directory has been created');
});