What Is The JavaScript Require Function & Why Is It Important?

Athena Ozanich
Athena Ozanich


JavaScript is a robust language that started out very simple and has grown into one of the most popular programming languages today. Due to how powerful it is, there is a lot to learn on the subject, and some things are less known, such as the JavaScript require function.

A young woman learns what the JavaScript require function is and how she can use it to enhance her software development process.

In this post, you will learn about the JavaScript require function, what it does and how it can improve your programming. You will also learn how it differs from the import function and when you would want to use one over the other. Finally, you'll see a brief example of the syntax for using the JavaScript require function.

Let's get started.

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What is the JavaScript require function?

The JavaScript require function facilitates a way to include JavaScript modules in your code. These modules are essentially the same as a JavaScript library, though modules are typically smaller. Modules are JavaScript files that usually only have a few lines of code. They often contain classes and functions that improve your code by simplifying the primary files for your software. Look at the next image to see an example of the require function.

A screenshot of the JavaScript require function used in a JavaScript file.Image Source

By including modules, your primary files can contain less code and become easier to read, navigate and debug. Human readable code is a common goal that many programmers aim to achieve, which modules and libraries make much more manageable.

Furthermore, modules can be reused in other software without the need to rewrite your functions and support the OOP architecture. However, you need to include the external files in your primary file to accomplish these improvements. That is where the JavaScript require function and import come into play.

How To Use The JavaScript Require Function

Using the require function is easy, and the syntax is simple too. Let's look at the code below to explore the syntax behind the JavaScript require function.

var varName = require(locationName);

The code above is only the general syntax. Let's look at the syntax for including an external module from a web-based location.

var myVar = require('http://location');

The syntax for including a local file is very similar. You need to pass into the function a reference to the local address for the file you wish to include. In either case, the filename you pass in must have the .js extension.

var myVar = require('./location');

In the above code, the dot notation used in the file address signifies the root location of the calls originating folder.

The import function performs similarly with one clear difference; it always runs the file to which it points. Furthermore, the import function can only be run at the beginning of the file, whereas the require function can include files conditionally.

The import function works the same. However, the file extension must be of the type .mjs and cannot be used to load JSON files. The syntax for the import function looks like the code in the example below.

var myVar = import("module-name");

What's next in using the JavaScript require function?

This post covers everything you need to know to use the require function. You have learned about the syntax for both ways to use the require function to include either a local or non-local file. Moving forward, the best way to further understand the require function is to put it to use by writing some code and using require to include files in your software's file.


Topics: Javascript

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