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September 4, 2021

React Explained – What is React?

Table of Contents

If your goal is to develop a next-gen Web3 application and would like to incorporate an efficient UI, then you’ve probably heard of React. When it comes to building user interfaces, React’s JavaScript library is currently the most popular one. However, if you’ve just started your development journey, then it would be a good idea to discover what React is and its various use cases. Therefore, we’ll be doing an in-depth overview of React by answering questions such as “what is React?”. We’ll also show how you can leverage Moralis and its powerful Web3 platform to create impressive Web3 applications.

What is React? 

So, what is React? Well, React (also known as React.js) is an open-source, declarative JavaScript UI library used for building an interactive user interface. React was originally built by Facebook, and it’s a collection of pre-written JavaScript code that abstracts away routine UI processes, helping developers to focus solely on building efficient UIs. To experience the many benefits of React, having some type of basic JavaScript knowledge would be necessary. However, you don’t need to be a JavaScript expert, so there’s no need to worry. React.js also uses a templating language called JSX that compiles your code to plain JavaScript functions.

React.js is declarative, meaning that it predictably uses our code and takes care of all the necessary JavaScript DOM (Document Object Model) manipulations required to get our desired result. This empowers you to create large, and efficient applications, especially single-page applications (SPAs), that render data changes without unnecessary page reloads. 

To achieve this, React has a couple of features that make creating appealing user interfaces straightforward and exciting. These features have contributed to making it the most popular UI library in the world.

Key Features of React.js

Now that you can answer fundamental questions such as “what is React?”, let’s look at some important React peculiarities. Some of the most important features are:

  • Reusable components.
  • One-way data flow.
  • JSX.
  • Virtual DOM.
  • React.js state management.

The following subheadings will explain key features that make it possible to build fast and scalable interactive UIs with React.js. So, let’s dig deep into these features and expand our React knowledge even further. 

What are Reusable Components?

Components are one of the powerful features of React.js, which are attractive to web developers. Understanding components is part of answering “what is React?”. A component is a reusable code block that acts independently from another element (therefore called a reusable component). This means that you can split an entire UI application into segments, with each part represented as a component. 

Components act like a JavaScript function that accepts data inputs via props and executes a “render()” function displaying the returned element. There are two types of components: function, and class components. Below are renditions of the same command rendered in the two types of components.

A cursory look will present some minor differences between the two. However, you must have noticed the “render()” method in the class component. The class component was the only type of component previously used for data management.

One-Way Data Flow

This was one of the distinct features of React.js when it first came out. With React, data moves in an expressive one-way directional flow. It exhibits a tree hierarchy format where data is passed down from top-level to child components. This feature means that child components cannot update data, giving you more extensive control over your application. 

Let’s use our “Welcome” component from the previous section as an example. The code snippet below shows how the one-way flow communicates using props.


JSX is an abbreviation that stands for “JavaScript XML”. JSX enables you to combine HTML markup and JavaScript function logic when creating UI elements. It also enforces the closing of tags as inspired by the XML language. Besides that, it also has standards, such as using “className” instead of “class”, and using “camelCase” for naming functions.

Although React can run without JSX, its usage gives the library a unique and elegant style. JSX can also serve as a visual aid for developers when building a UI.   

Virtual DOM

One of React’s powerful features is the virtual DOM. It allows the user to run specific changes without reloading the site’s DOM every time. To better appreciate how impressive this feature is, let’s look at how JavaScript interacts with the HTML DOM.

The HTML DOM is a hierarchical object structure that allows languages such as JavaScript to manipulate the DOM’s structure and elements programmatically. With the DOM, JavaScript can update all the HTML and CSS elements and attributes on the page. Whenever JavaScript access and updates the elements in the DOM, the web page reloads to reflect the new changes made by JavaScript. Now, imagine if you’ve got a massive application where the user can make several changes, this will put an enormous strain on the DOM leading to increased computing power usage and a long loading time.

The virtual DOM solves this dilemma by creating a copy of the actual DOM. Whenever the application makes a request, it notes these changes and looks at the virtual DOM’s specific part that requires an update without reloading the entire site’s DOM. This process results in a fast loading time and an application that’s less resource-intensive. 

React.js State Management

We’ve already talked about how React uses the virtual DOM to make necessary changes. These data changes shared across components causes the “state” of the app to change. It’s important to know that these changes may occur over the lifecycle of the components involved.

Knowing how to store the current state and track the data changes is vital to rendering your app interactively. This is called “state management”, and it’s the most important part to master when using React.

Because of the importance of effective state management, developing optimal state management libraries has received substantial attention. The most popular of these libraries is Redux. It works by creating a central store that stores various data states and allows components to access these changes. In addition to Redux, there’s also Recoil and MobX. 

However, the introduction of hooks has to a large extent, made it possible for developers to abandon these state management libraries. Hooks also made it possible to maintain a state without necessarily creating a class component. There’s the “useState” hook that helps function components manage the state. The “useEffect” hook allows you to perform critical side effects such as data fetching from APIs. There are also other hooks such as “useReducer”, “useContext”, and “useMemo”. You can even build custom hooks when you’ve mastered the original hooks. 

To fully use the powerful capabilities of React, it’s essential to have a good grasp of these features before you start building apps. 

What is React Used For?

So far, we’ve learned what React is, and the many features that have made React widely adopted in developing Web2 and Web3 applications. It’s now time to have a look at some common use cases of React. 

Building Interactive Web User Interfaces

This is literally what React was created for; empowering web developers to develop components that powers the user-facing frontend parts of an app. React builds on the power of JavaScript, helping you create and reuse essential UI features such as search bars, buttons, navigation panels, and a host of other web app features that users interact with. React’s simplicity and ease of use have made it the most popular frontend library that powers some of the biggest websites in the world.

Building Mobile Applications

Mobile apps are increasingly becoming the default way we interact with the web and the rest of the world. The introduction of “React Native”, an open-source project by Facebook, has entirely changed how we develop mobile apps. React Native has similar features as React, empowering developers who already know React to become mobile developers. Like React, React Native has been widely adopted and is one of the most popular tools used when building mobile applications today.

Game Development

The primary purpose of React was by no means game development. However, developers have created functionalities in React, such as a game engine that will help you develop games using React syntax. You can use React to build popular game prototypes such as Tetris, Pokemon, different quizzes, chess games, and RPG games. Another impressive thing you can do is to create an NFT game, which is possible when using Moralis.  

React vs JavaScript UI Frameworks

Although it has become the most popular JavaScript library for building user interfaces, frameworks such as Angular, Ionic, Svelte, and Vue.js have achieved some level of adoption. 

Many of these frameworks became famous quickly after being released to the market. However, when the time came to build large-scale web and mobile applications, developers soon abandoned them for the superior features of React. Although many still use the frameworks mentioned, you’ve probably realized that React maintains its leading position.

Let’s look at some of the reasons why React has reigned supreme over other UI libraries and frameworks:

  • Reusability – React introduced the concept of reusable components for creating UIs, and it has vastly changed the way we build user interfaces. Although recent frameworks such as Vue.js have integrated this feature, React’s first-mover advantage has ensured its continued stay at the top. 
  • Simplicity and Ease of Learning – Compared to an older framework such as AngularJS, React has a simpler process, and it’s easier to learn. All you need to know is HTML and basic JavaScript, and you’re well on your way to building an application with React.
  • Performance – React.js is great when building flexible and efficient web and mobile applications. The virtual DOM has also boosted its performance metrics over a plain JavaScript or jQuery app.

Excellent Developer Experience

React.js provides one of the best experiences for developers. This is mainly because of the support from Facebook and its enormous resources. React.js has rich and in-depth documentation, and it’s also widely integrated with popular developer productivity tools such as IDEs and automated deployment tools. The “create-react-app” also helps you to quickly set up a standard app in seconds with a single command.

Furthermore, because of its widespread adoption, a vibrant community releases tons of third-party tools and templates that will make your work easier.

These reasons and more are why React has maintained its number one position and is the primary choice even by new developers.

Best Strategy for Learning React.js in 2021

Here at Moralis, we’ve designed two simple steps to help you become a brilliant React.js developer.

Step 1: Learn React.js Fundamentals

From reading this article so far, you now understand what React entails and its unique features and use cases. In short, you can now answer “what is React” with ease. If you want to take a deeper dive into React.js fundamentals such as JSX or state management, and learn how to use React, then make sure to check out this excellent course called “React Web Development 101” on Ivan on Tech Academy – sign up today! 

Step 2: Build Projects

The fastest way to become a solid React developer is by building projects. However, it’s impossible to learn all the intricacies of React’s ecosystem. So, the best way to ingrain all the fundamentals you’ve learned and help you gain more skills is to put everything you’ve learned into practice.

If you desire to become a Web3 developer, we would recommend learning and taking advantage of Moralis. With Moralis, you can quickly build Web3 applications, create NFT games, and much more. Moralis is a Web3 development platform that provides everything you need to develop, host and scale serverless Web3 apps. You can create everything from BSC dApps to smart contracts. The list of Web3 apps you can create with Moralis is endless.

So, after answering “what is React”, you might ask yourself “how does React work with Moralis?”. Well, you can use React with Moralis to build an extensive range of excellent Web3 apps easily and quickly. There are reusable components, and custom React hooks for Moralis that can help you easily interact with powerful Moralis SDK features in displaying Web3 data in your app. Furthermore, Moralis provides rich documentation showing you how to authenticate your app easily in a couple of seconds, amongst many other features.  

With Moralis, you can devote all your efforts to creating appealing and interactive user interfaces while easily integrating Moralis as your backend service. Start creating amazing dApps using Moralis today!

What is React? – Summary

This article has been quite extensive. At first, we introduced you to what the React.js library is, answering potential questions you might have, such as “what is React?”. Also, we briefly examined the powerful features that have made React.js the most popular choice when building UIs. Furthermore, we’ve also discussed some everyday use cases of React, such as game development. We explored JavaScript frameworks that want to compete with React, but we highlighted areas where React excels and has helped it establish its number one position. You’ll now be able to confidently answer “what is React” and also employ React in building your dApps.

Finally, we shared an effective learning strategy that will help you become a skilled developer of decentralized applications using Moralis. So, what are you waiting for? Sign up with Moralis today, and let us guide you in your development journey!

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