CommonJS require and module.exports in Node.js - Mini Project: Build & Apply

CommonJS require and module.exports

📖 Scenario: You are building a simple Node.js app that uses CommonJS modules to organize code. You want to create a module that exports a greeting function, then import and use it in your main file.

🎯 Goal: Create a module file that exports a function using module.exports, then import it in another file using require and call the function.

📋 What You'll Learn

Create a file named greet.js that exports a function called sayHello using module.exports.

The sayHello function should return the string 'Hello, Node.js!'.

Create a file named app.js that imports the sayHello function from greet.js using require.

Call the imported sayHello function in app.js.

💡 Why This Matters

🌍 Real World

Node.js uses CommonJS modules to organize code into reusable pieces. This helps keep projects clean and manageable.

💼 Career

Understanding CommonJS modules is essential for backend JavaScript development and working with many Node.js projects.

1

Create the greet.js module with sayHello function

Create a file named greet.js. Inside it, define a function called sayHello that returns the string 'Hello, Node.js!'.

Node.js

// Define the sayHello function
// Your code here

Need a hint?

Define a function named sayHello that returns the greeting string.

2

Export the sayHello function using module.exports

In greet.js, export the sayHello function using module.exports.

Node.js

function sayHello() {
    return 'Hello, Node.js!';
}

// Export sayHello function
// Your code here

Need a hint?

Assign the sayHello function to module.exports to export it.

3

Import the sayHello function in app.js using require

Create a file named app.js. Import the sayHello function from greet.js using require and store it in a variable called sayHello.

Node.js

// Import sayHello function from greet.js
// Your code here

Need a hint?

Use require('./greet') to import the exported function and assign it to sayHello.

4

Call the sayHello function in app.js

In app.js, call the sayHello function.

Node.js

const sayHello = require('./greet');

// Call sayHello function
// Your code here

Need a hint?

Simply call the sayHello() function to use it.