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Welcome to the ‘What, Why?’ series hosted by Entrance. The goal of this series is to take different technologies and examine them from a technical perspective to give our readers a better understanding of what they have to offer. The web is filled with tons of resources on just about anything you could imagine, so it can be really challenging to filter out all of the noise that can get in the way of your understanding. This series focuses on the two biggest cornerstones of understanding new tools: What is it, and why use it? So, without further ado, let’s kick off this first edition with something you’ve probably heard of: React!

React, quite simply, is getting big. It’s one of the most starred JavaScript Libraries on GitHub, so it goes without saying that it’s garnered lots of followers, as well as fanboys. React was originally developed by Facebook for internal use and many will be quick to point out that instagram.com is completely written with React. Now, it’s open source and backed by not just Facebook, but thousands of developers worldwide and considered by many to be the ‘future of web development’. React is still new-ish, but has had time to mature. So, what is it?

What is React?

A JavaScript Library

First and Foremost: React is a JavaScript Library. Even if some call it a framework, it is NOT. It is ONLY a view layer. What is the purpose of the library? To build User Interfaces. React presents a declarative, component-based approach to UIs, aimed at making interfaces that are Interactive, stateful, and reusable. It revolves around designing your UI as a collection of components that will render based on their respective states.

Paired with XML Syntax

React is also often paired with JSX or JavaScript XML. JSX adds XML syntax to JavaScript, but is NOT necessary in order to use React. You can use React without JSX, but having it would definitely help make things more clean and elegant.

‘Magical’ Virtual DOM

A distinguishing aspect of React is that uses something magical called ‘The Virtual DOM’. Conceptually, virtual DOM is like a clone of the real DOM. Let’s make the analogy of your DOM being a fancy schmancy new sports car of your choice. Your virtual DOM is a clone of this car. Now, let’s say you want to trick out your sweet new ride with some killer spinny-rims, wicked flames decals on the sides and, the classical cherry-on-top, a pair of fuzzy dice hanging from the rear-view mirror. When you apply these changes, React runs a diffing algorithm that essentially identifies what has changed from the actual DOM (the car) in your virtual DOM (your now-tricked-out clone). Next, it reconciles the differences in the Real DOM with the results of the diff. So, really, instead of taking your car and completely rebuilding it from scratch, it only changes the rims, sides, and rear-view mirror!

Why React?

Component Modularity

Now that we’ve got a reasonable understanding of what React is, we can ask: Why use it? One of the biggest pluses to React is the modularity caused by its paradigm. Your UI will be split into customizable components that are self-contained and easily reused across multiple projects; something everyone can appreciate. Not only that, but components make testing and debugging less of a hassle as well.

Popular Support

The popularity of React also plays to its advantage. Being fully supported by Facebook AND thousands of developers means there will be plenty of resources around for your perusing, and tons of knowledgeable, friendly folks eager to help you if you get stuck along the way. That also means there’s plenty of people working towards constantly improving the React library!

JSX + Virtual DOM

JSX is a nifty little plus in that, while it’s not required, you are able to use it, making the writing and maintaining of your components even more straightforward and easy.

Great Performance

Topping off our list of Pros, we’ve got the Virtual DOM. It opens up the capability of server side rendering, meaning we can take that DOM clone, render it on our server, and serve up some fresh server-side React views. Thanks to Reacts Virtual DOM, pages are quicker and more efficient. The performance gains are quite real when you are able to greatly reduce the amount of costly DOM operations.

Why Not React?

As great as anything is, it can be just as important to know why you SHOULDN’T use it. Nothing is the perfect tool for absolutely everything, so why wouldn’t you use React? Well…

Don’t Use React Where it’s Not Needed

React shines when you’ve got a dynamic and responsive web content to build. If your project won’t be including any of that, React might just not be needed, and could result in you adding a lot of unnecessary code. Another downer is that, if you did opt to avoid pairing JSX in with your react components, your project can get kind of messy and harder to follow.

Understand the React Toolchain

Some people don’t realize that React only represents the View. That means you’ll have to be bringing in other technologies in order to get something fully functioning off the ground. Developers typically recommend using Redux with React, as well as Babel, Webpack, NPM… so if you’re not already familiar with the common accompaniments of React, you could end up biting off a bit more that you want to chew.

So in the end, should you use React? Is the hype train worth jumping on? Well, that’s completely dependent on your project and the constraints involved. It’s something that you and your team will have to decide together. Hopefully after reading this article, you are able to recognize what React is, as well as why you should keep in in mind for the future. If you’re interested in a deeper dive into the subjects discussed here, check out the React site! We hope you were able to take away some good info from this edition of ‘What, Why?’, and if you’re looking for more, be on the lookout for our upcoming post on React-Native!


Nicolae Taylor
Junior Software Consultant @ Entrance
Carol Entrance Software Consulting making software better