Why we use React Js?

What is React JS?

React JS is a JavaScript library used in web development to build interactive elements on websites. But if you’re not familiar with JavaScript or JavaScript libraries, that’s not a helpful definition. So let’s take a step back and deal with those terms first.


From the definition above, you can see how JavaScript plays a critical role in website and web application development. But there are times when you need JavaScript to perform repetitive functions—things like stock animation effects or autocomplete search bar features. Re-coding these functions every time they occur becomes a “reinventing the wheel” situation. Annnnoying. This is where JavaScript libraries come in.

JavaScript libraries are collections of pre-written JavaScript code that can be used for common JS tasks, allowing you to bypass the time intensive (and unnecessary) process of coding by hand. If there’s a run-of-the-mill JavaScript function that you keep needing to code (and that other developers before you have needed for their own projects) there’s probably a JS library to ease your pain. Make sense?

What is React JS used for, and why should you learn React JS? And is it better than other JavaScript libraries?

Why Do JavaScript Developers Use React JS?

React is a JavaScript library that specializes in helping developers build user interfaces, or UIs. In terms of websites and web applications, UIs are the collection of on-screen menus, search bars, buttons, and anything else someone interacts with to USE a website or app.

Note: readers often ask “is React JS frontend or backend?” The answer is: definitely frontend. You can keep this straight by remembering the “on screen” aspect of UIs—React is used exclusively for “client side” programming (building things that a user will see on screen in their browser window), which makes React JS a frontend library.

Before React JS, developers were stuck building UIs by hand with “vanilla JavaScript” (developer speak for the raw JavaScript language on its own) or with less UI-focused React predecessors like jQuery. That meant longer development times and plenty of opportunities for errors and bugs. So, in 2011, Facebook engineer Jordan Walke created React JS specifically to improve UI development.

In addition to providing reusable React library code (saving development time and cutting down on the chance for coding errors), React comes with two key features that add to its appeal for JavaScript developers:

  • JSX
  • Virtual DOM

To get an even better understanding of React JS and why you should use it, let’s take a look at both.


At the heart of any basic website are HTML documents. Web browsers read these documents and display them on your computer, tablet, or phone as web pages. During this process, browsers create something called a Document Object Model (DOM), a representational tree of how the web page is arranged. Developers can then add dynamic content to their projects by modifying the DOM with languages like JavaScript.

JSX (short for JavaScript eXtension) is a React extension that makes it easy for web developers to modify their DOM by using simple, HTML-style code. And—since React JS browser support extends to all modern web browsers—JSX is compatible with any browser platform you might be working with.

This isn’t just a matter of convenience, though—using JSX to update a DOM leads to significant site performance improvements and development efficiency. How? It’s all about the next React feature, the Virtual DOM.

Virtual DOM

Considered the next biggest leap in web development since AJAX, the virtual DOM (short for Document Object Model) is the core reason why React enables the creation of fast, scalable web apps. Through React’s memory reconciliation algorithm, the library constructs a representation of the page in a virtual memory, where it performs the necessary updates before rendering the final web-page into the browser.

What Does React JS Code Look Like?

If all of this makes sense but you’re still wondering, “what IS React code?” you can get a visual idea of what React looks like straight from this React examples website. Each of the projects listed here gives an idea of what’s possible with React JS and a look at the source code used to build it.

Toolkit for Developers.

It has made a widespread toolkit for the developers. These tools allow users to design and debug any problems with ease. The toolkit also has a browser extension that can be downloaded and used for both Chrome and Firefox. This extension, called React Developer Tools, is great for developers that want to analyze the initial, new and reactive components and see what the possible outcomes are.

Easy to learn

We need to clarify that React is NOT a framework; unlike Angular or Vue.js, but a library that is consistently used in association with other Javascript libraries. Hence, there is a shorter learning curve involved in understanding React compared to other comprehensive libraries. Businesses; in turn, are able to streamline development without spending much capital on the existing system.