How To Export A Function In Javascript

In JavaScript, there are several ways to export a function from one module, so you can easily use it in another module. In this blog post, we will explore the two most common methods: using the module.exports and export keywords.

Method 1: Using module.exports

This method is commonly used in Node.js applications, where you have a separate file for each module. It allows you to export a single function, an object containing multiple functions, or even a class.

To demonstrate this, let’s create a simple function called sayHello that we want to export:

function sayHello(name) {
    console.log(`Hello, ${name}!`);

To export this function, all you need to do is assign it to the module.exports object:

module.exports = sayHello;

If you want to export multiple functions, you can create an object with the functions as its properties:

function sayGoodbye(name) {
    console.log(`Goodbye, ${name}!`);

module.exports = {

To use the exported function(s) in another module, you simply need to require the module and call the function:

const greetings = require('./greetings.js');


Method 2: Using the export keyword (ES6 Modules)

With the introduction of ES6, JavaScript gained a new way of exporting and importing modules called ES6 Modules. This method is more versatile and can be used in both Node.js and modern browsers.

To export a function using ES6 Modules, you simply need to add the export keyword before the function declaration:

export function sayHello(name) {
    console.log(`Hello, ${name}!`);

If you want to export multiple functions, you can use the export keyword with each function declaration:

export function sayGoodbye(name) {
    console.log(`Goodbye, ${name}!`);

To use the exported function(s) in another module, you can use the import keyword:

import { sayHello } from './greetings.js';


Or, if you are importing multiple functions, you can use a single import statement:

import { sayHello, sayGoodbye } from './greetings.js';



Exporting and importing functions in JavaScript is a fundamental part of modular programming, allowing you to create reusable and maintainable code. Whether you’re using module.exports in a Node.js application or export in ES6 Modules, the process is simple and straightforward, making it easy to share your functions across your entire project.