Creating custom modules in Node.js

Node.jsJavascriptWeb DevelopmentFront End Technology

The node.js modules are a kind of package that contains certain functions or methods to be used by those who imports them. Some modules are present on the web to be used by developers such as fs, fs-extra, crypto, stream, etc. You can also make a package of your own and use it in your code.

Syntax

exports.function_name = function(arg1, arg2, ....argN) {
   // Put your function body here...
};

Example - Custom Node Module

Create two file with name – calc.js and index.js and copy the below code snippet.

The calc.js is the custom node module which will hold the node functions.

The index.js will import calc.js and use it in the node process.

calc.js

//Creating a custom node module
// And making different functions
exports.add = function (a, b) {
   return a + b; // Adding the numbers
};

exports.sub = function (a, b) {
   return a - b; // Subtracting the numbers
};

exports.mul = function (a, b) {
   return a * b; // Multiplying the numbers
};

exports.div = function (a, b) {
   return a / b; // Dividing the numbers
};

index.js

// Importing the custom node module with the below statement
var calculator = require('./calc');

var a = 21 , b = 67

console.log("Addition of " + a + " and " + b + " is " + calculator.add(a, b));

console.log("Subtraction of " + a + " and " + b + " is " + calculator.sub(a, b));

console.log("Multiplication of " + a + " and " + b + " is " + calculator.mul(a, b));

console.log("Division of " + a + " and " + b + " is " + calculator.div(a, b));

Output

C:\home\node>> node index.js
Addition of 21 and 67 is 88
Subtraction of 21 and 67 is -46
Multiplication of 21 and 67 is 1407
Division of 21 and 67 is 0.31343283582089554
raja
Published on 20-May-2021 11:16:09
Advertisements