Difference between module.exports and exports in Node.js

The module is a plain JavaScript Object representing the current module. It is local to each module and also it is private. It has exports property which is a plain JavaScript variable, set to module.exports. At the end of the file, Node.js return module.exports to the required function.

About module.exports: 

When we want to export a single class/variable/function from one module to another module, we use module.exports.

Example: Create two files calculator.js and operation.js and export the Arithmetic class from calculator.js to operation.js using module.exports method. Here, we have created a class Arithmetic and exported the whole class using module.exports.

Filename: calculator.js

Javascript

class Arithmetic {
    constructor(a, b) {
        this.a = a;
        this.b = b;
    }

    add() {
        return this.a + this.b;
    }
    subtract() {
        return this.a - this.b;
    }

    multiply() {
        return this.a * this.b;
    }

    divide() {
        if (this.b != 0) {
            return this.a / this.b;
        }
        return "divided by zero !!!!";
    }
};

module.exports = Arithmetic;

Filename: operation.js

Javascript

const Arithmetic = require('./calculator.js');

const op = new Arithmetic(100,40);

console.log(`Addition -> ${op.add()}`);
console.log(`subtraction -> ${op.subtract()}`);
console.log(`Multiplication -> ${op.multiply()}`);
console.log(`Division -> ${op.divide()}`);

Run the operation.js file using the following command:

node operation.js

Output:

Using module.exports 

About exports: 

When we want to export multiple variables/functions from one module to another, we use exports.

Example: Create two files calculator.js and operation.js and export multiple functions from calculator.js file. 

Filename: calculator.js

Javascript

exports.add = (a, b) => a + b;
exports.subtract = (a, b) => a - b;
exports.multiply = (a, b) => a * b;
exports.divide = (a, b) => {
    if (b != 0) {
        return a / b;
    }
    return `Divided by zero !!!`;
}

Filename: operation.js

Javascript

const Arithmetic = require('./calculator.js');

console.log(`Addition -> ${Arithmetic.add(100,40)}`);
console.log(`subtraction -> ${Arithmetic.subtract(100,40)}`);
console.log(`Multiplication -> ${Arithmetic.multiply(100,40)}`);
console.log(`Division -> ${Arithmetic.divide(100,40)}`);

Run the operation.js file using the following command:

node operation.js

Output:

Using exports

Key differences between module.exports and exports:

S.no	Module.exports	Exports
1	When we want to export a single class/variable/function from one module to another module, we use the module.exports way.	When we want to export multiple variables/functions from one module to another, we use exports way.
2.	It is the object reference that gets returned from the require() calls.	exports is not returned by require().  It is just a reference to module.exports.