Is JavaScript used on frontend or backend?

Today, we rely on technological tools like websites and mobile apps. We are only a click away from anything from getting a cab to booking hotels. But have you ever thought about how developers build these apps? Is JavaScript used on frontend or backend? How do these applications store data? How are the appealing user interfaces made? The answer is JavaScript.

This post will discuss how we can use JavaScript to build everything from front-end web apps to back-end systems. We’ll also look at the many JavaScript runtimes available for usage.

What is JavaScript?

Brendan Eich introduced JavaScript, a dynamically typed scripting language, in 1995. Its primary purpose was to use the Netscape Navigator web browser to enhance the user experience by making websites more dynamic and interactive. Since then, JavaScript has dramatically changed. JavaScript has evolved from being primarily used for scripting to being the most versatile and well-liked programming language ever.

How is JavaScript executed?

Due to JavaScript’s interpretive nature, we read and process our code one line at a time instead of all at once. A JavaScript Engine is responsible for running our JavaScript code. It has a call stack, just like other languages, where the functions are pushed and popped.

Apart from a JavaScript Engine, we also need a JavaScript runtime environment. In JavaScript, the runtime environment provides programs access to built-in libraries and objects that allow them to interact with the outside environment. We may use a car engine as an example. The most significant component of an automobile is the engine, which we use to propel the vehicle. However, to operate a car engine, we need a chassis, wheels, accelerator, braking clutch, and so on. Similarly, for JavaScript to run, we also require a JavaScript runtime environment in addition to the JavaScript Engine.

So, given a JavaScript runtime environment, can we run JavaScript anywhere? Yes, as long as we have a JavaScript runtime environment, we can use JavaScript anywhere, from browsers to servers.

JavaScript for the front-end

Brenden Eich initially created JavaScript to improve the interactivity of front-end web applications. Users can interact with web pages using JavaScript. On a web page, you can accomplish a lot using JavaScript. Here are some examples:

1. Fetch some information from a server.
2. Send some info to the server.
3. Easily display or hide information by clicking a button.
4. Put a timer on the website.
5. Validate form submissions.

In the past, developers used pure JavaScript for creating user interfaces. Several libraries are available, like React.js, Vue.js, SvelteKit, and others. These libraries and frameworks have significantly increased the use of JavaScript in front-end development.

JavaScript for the back-end: Node.js

Node.js is a JavaScript runtime built on the V8 Engine from Google. Ryan Dahl made it available as open-source software on May 27, 2009. Since then, Node.js has grown in popularity and is currently the most used JavaScript runtime for running JavaScript on the server side.

We can use JavaScript for much more than simply creating interactive websites with Node.js. It can perform tasks similar to those performed by other scripting languages, such as Python.

Here are a few of the excellent features that make Node.js so popular.

Asynchronous and Event-Driven architecture

The APIs of the Node.js library is entirely asynchronous (non-blocking). Furthermore, Node.js uses events a lot, which is one of the reasons it is faster than other comparable technologies.

Single-Threaded

Node.js is highly scalable since it has a single-threaded architecture with an event loop. The event mechanism makes the node.js server more scalable and enables it to respond in a non-blocking way, in contrast to conventional servers that only produce a small number of threads to handle requests.

Cross Platform

Node.js is platform-independent. For example, a Node.js developer may construct a cross-platform desktop application for Windows, Linux, and Mac. Furthermore, Node.js is not limited to mobile, desktop, and web development. People actively use the benefits of Node.js in creating cloud or IoT applications.

Other emerging JavaScript runtimes

Aside from Node.js, additional new JavaScript runtimes have come up in recent years. These runtimes offer some excellent capabilities that Node.js currently lacks. Let’s look at some of the most popular JavaScript runtimes that emerged in recent years.

Deno

Deno is an entirely new JavaScript runtime. Ryan Dahl, the inventor of Node.js, developed it. It came out in 2018. Dahl had a few regrets with Node and wanted to create a runtime that might address those shortcomings. Deno aims to bring server-side JavaScript comparable to browser JavaScript.

Deno’s most notable features are as follows:

1. Deno supports typescript out of the box. It implies you can execute or utilize TypeScript without needing additional external or third-party packages.
2. Deno primarily supports the ES Module system and does not support the CJS module system. It means that we may utilize newer import statements with Deno.
3. Deno is, by default, safe. Unless explicitly permitted, the script cannot access system files, the network, or the environment.

In comparison to Node, Deno offers many advantages. Security by default feature is attractive, and TypeScript out-of-the-box support is a big plus for developers.

Bun

Jared Sumner introduced the Bun, a revolutionary, lightning-fast JavaScript runtime, in 2022. The Bun runtime utilizes the Zig programming language, which embraces web standards and Node.js APIs. With Bun, developers can easily migrate their existing code of Node.js APIs. Bun, unlike Node.js and Deno, employs the JavaScriptCore as its engine. Several apps on macOS use JavaScriptCore, including Safari, Mail, and the App Store.

Bun’s most notable features are as follows:

1. It has built-in web APIs, such as fetch, WebSockets, and ReadableStreams.
2. Using npm packages in Bun is possible thanks to Bun’s implementation of Node.js’ module resolution algorithm.
3. It is possible to use both ESM and CommonJS.
4. Bun implements several Node-API features.

In addition to being extremely quick, Bun has certain appealing features that make many more boring operations, such as writing files, maintaining essential databases, and manipulating environmental variables, pretty simple.

Conclusion

This article addressed how much today’s web-based applications rely on JavaScript. JavaScript covers whether you want to develop code for the front end or the back end. We studied how JavaScript functions by using a JavaScript runtime environment. Because of these runtimes, we can utilize JavaScript anywhere, including on servers. In addition, we addressed Node.js, the most popular JavaScript runtime. We also looked at various emerging next-generation JavaScript runtimes that have outstanding features.

We can create web apps, server-side applications, desktop applications, mobile applications, games, machine learning, and other things with simply JavaScript. Thanks to JavaScript, building apps has never been simpler. Now is the ideal opportunity to discover JavaScript and all the goodness it has to offer.

Thank you so much for reading ?