ReactJS: one of the most popular JavaScript libraries

ReactJS: one of the most popular JavaScript libraries
Photo by Lautaro Andreani / Unsplash

Created by Facebook, React contains a collection of reusable JavaScript code snippets focused on building user interfaces.

The web development industry has experienced constant growth in recent years; And as this growth continues, new technologies are constantly emerging to help developers create user-friendly websites and web applications. Currently, there are various technologies intended to develop web applications. One is JavaScript's React. Today we will tell you what React JS is, how it works and what its advantages are... Let's get started!


In a nutshell, ReactJS is one of the most popular JavaScript libraries for mobile and web app development. However, it is important to mention that ReactJS is not a JavaScript framework. This is because it is only responsible for rendering the view layer components of an application. React is an alternative to frameworks like Angular and Vue.

React has been used by many front-end engineers at both startups and established companies like: Facebook, Netflix, Instagram, Yahoo, Uber, The New York Times, and more. Although all of the companies mentioned did not build their entire product with React, some of their pages were built with React. This is due to the high performance it offers, the ease of use and its scalability.

More specifically, React is generally used to build the frontend of web applications. It offers fast page rendering and increased performance. We can use it for:

  • Music player apps.
  • Social networking apps.
  • Chat applications in real time.
  • Full stack web applications.
  • E-commerce applications.
  • Weather apps.
  • To-do list apps.

Some of the main features of React are:

  • JSX: This is an extension to the JavaScript syntax that extends the features of ES6. It allows us to combine JavaScript logic and markup in one component.
  • Virtual DOM: This is a copy of the DOM object that first updates and re-renders our pages when changes are made; then it compares the current state with the original DOM to keep it in sync with the changes. This makes page rendering faster.
  • Components: React apps are made up of different reusable components that have their own logic and user interface. This makes it efficient for scaling applications and maintaining high performance because you don't duplicate code as often as in other frameworks.
Photo by Rahul Mishra / Unsplash

Advantages and disadvantages of React

React may be a very popular tool for building our user interface, but there are still reasons why some developers are hesitant to use it. Here are some of its advantages and disadvantages:


  1. React is easy to learn and understand.
  2. React has a very active community where you can contribute and get help when you need it.
  3. There are many job opportunities for React developers.
  4. React offers higher application performance.


  1. Beginners without a solid understanding of JavaScript (especially ES6) may have a hard time understanding React.
  2. React comes without some common functionality like single state management and routing; you would have to install and learn how to use external libraries.

An extremely important feature of ReactJS is that it can improve the search engine optimization (SEO) of web applications by increasing their performance. The implementation of the virtual DOM is one of the factors that influence a higher speed of the pages.

Additionally, React helps search engines navigate web applications through server-side rendering. This addresses one of the biggest problems JavaScript-heavy websites have, as search engines often find them difficult and slow to crawl.

React vs React Native

Despite having similarities, React Native is different from ReactJS. React Native is an open source JavaScript framework built on top of the React library. Developers use it to build cross-platform React apps for iOS and Android.

React Native uses native application programming interfaces (APIs) to render mobile UI components in Objective-C (iOS) or Java (Android). Thanks to this, developers can create specific components for each platform and share the source code in several of them. So that you can understand it better, we show you a quick comparison of React Native and ReactJS:

  • While ReactJS is a JavaScript library, React Native is a JavaScript framework.
  • ReactJS is ideal for building dynamic web applications while React Native gives a native feel to the user interface of mobile applications.
  • ReactJS uses the virtual DOM to render browser code; React Native uses the native APIs to render code on mobile devices.
  • With ReactJS we have CSS to create animations while React Native requires the API to animate components.

We hope that we have helped you understand a little more about React JS and its functions in web development. At e·Saurio we are experts in technology and software development, which is why every Wednesday we share with you an article that we know will be very useful for you.

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