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 way.
Example: Create two file 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 Artimatics { 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 = Artimatics; |
Filename: operation.js
Javascript
const Artimatics = require('./calculator.js'); const op = new Artimatics(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 a two file 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 Artimatics = require('./calculator.js'); console.log(`Addition -> ${Artimatics.add(100,40)}`);console.log(`subtraction -> ${Artimatics.subtract(100,40)}`);console.log(`Multiplication -> ${Artimatics.multiply(100,40)}`);console.log(`Division -> ${Artimatics.divide(100,40)}`); |
Run the operation.js file using the following command:
node operation.js
Output:
Using exports
Key difference between module.exports and exports: S.no Module.exports Exports 1 2.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. It is the object reference that gets returned from the require() calls. The exports is not returned by require()
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