Today, I continued my Node.js learning journey with the help of AI, and the topic for Day 2 was the module system in Node.js. Since I'm already familiar with JavaScript, it was interesting to learn how this language organizes code into modules, making it easier to structure and reuse.

Theoretical Part: Basics of Modules in Node.js

First, I went through the theoretical part, which explained two key concepts:

1. require: This function is used to import modules into your code. When you call require('module_name'), Node.js finds the specified module and returns its content. This can be a built-in module, a module from the node_modules package, or your own custom module.

2. module.exports: This object is used to export functionality from a module so that it can be used by other modules via require. You can export functions, objects, variables, or classes.

These concepts were new to me in the context of Node.js, but similar to what I’ve seen in other programming languages.

Practical Application: Creating Modules

I started by creating several modules for different mathematical operations, as suggested in the article.

1. addition.js: This module performs addition.
   

   function add(a, b) {
       return a + b;
   }
   
   module.exports = add;
   

2. subtraction.js: A module for subtraction.
   

   function subtract(a, b) {
       return a - b;
   }
   
   module.exports = subtract;
   

3. multiplication.js: A module for multiplication.
   

   function multiply(a, b) {
       return a * b;
   }
   
   module.exports = multiply;
   

4. division.js: A module for division.
   

   function divide(a, b) {
       if (b === 0) {
           return 'Error: Division by zero';
       }
       return a / b;
   }
   
   module.exports = divide;
   

After creating these modules, I started writing the main file that would use them.

1. calculator.js: In this file, I imported all the modules I created and wrote code to perform arithmetic operations.
   

   const add = require('./addition');
   const subtract = require('./subtraction');
   const multiply = require('./multiplication');
   const divide = require('./division');
   
   console.log("Addition: 5 + 3 =", add(5, 3));
   console.log("Subtraction: 5 - 3 =", subtract(5, 3));
   console.log("Multiplication: 5 * 3 =", multiply(5, 3));
   console.log("Division: 6 / 2 =", divide(6, 2));
   

Expanding the Functionality

After completing the basic operations, I decided to challenge myself by adding new functions to the calculator. I created additional modules for exponentiation and square root:

1. exponentiation.js: A module for exponentiation.
   

   function exponentiate(base, exponent) {
       return Math.pow(base, exponent);
   }
   
   module.exports = exponentiate;
   

2. sqrt.js: A module for calculating the square root.
   

   function sqrt(number) {
       return Math.sqrt(number);
   }
   
   module.exports = sqrt;
   

I added these to the main file calculator.js, and now my calculator supported extended operations:

const add = require('./addition');
const subtract = require('./subtraction');
const multiply = require('./multiplication');
const divide = require('./division');
const exponentiate = require('./exponentiation');
const sqrt = require('./sqrt');

console.log("Addition: 5 + 3 =", add(5, 3));
console.log("Subtraction: 5 - 3 =", subtract(5, 3));
console.log("Multiplication: 5 * 3 =", multiply(5, 3));
console.log("Division: 6 / 2 =", divide(6, 2));
console.log("Exponentiation: 2 ^ 3 =", exponentiate(2, 3));
console.log("Square root of 16 =", sqrt(16));

Results and Conclusions

By applying the theory in practice, I gained a better understanding of how modules help organize code and how easy they are to use in Node.js. Working with separate files for each operation made me realize the importance of modularity and how it improves code readability and scalability.

This experience showed me how crucial it is to organize code properly, especially as a project becomes more complex. Now I feel confident working with modules in Node.js and am ready for the next step in my learning journey.

For more details on this lesson, you can refer to the full tutorial here.

This is how I learned from the article and understood how modules work in Node.js through practical application.