What is React JS?

Introduced in 2011 React JS  has been in use since May 2013. ReactJS is a free and open-source JavaScript toolkit for creating user interfaces for online applications. It was built by Facebook and is now maintained by Facebook and a developer community. Developers may use ReactJS to create sophisticated and reusable UI components, making the development process more efficient and the resultant apps more scalable.

It offers various extensions except just for mere UI, for application architectural support. It is a comparatively new technology and has improved performance. In this blog, we will learn what is React JS, its components, concepts, uses and features in-depth.

React JS Overview

A user interface development library based on a JavaScript framework is called React, used by open-source developer communities, like Facebook. It is one of the most popular and used libraries for web development. 

A component in ReactJS is a piece of reusable code that may be used to generate user interface components. Complex user interfaces may be created by combining components.

As a user interacts with the UI, ReactJS updates it using a virtual DOM (Document Object Model). The virtual DOM is a lightweight duplicate of the actual DOM that allows for quicker UI updates.

ReactJS makes use of JSX, a JavaScript syntax extension that allows developers to create HTML-like code within JavaScript. This simplifies the creation and management of components.

ReactJS features a robust ecosystem of third-party libraries and tools, including Redux for state management and React Router for client-side routing.  

ReactJS has a promising future in the web development business as it is one of the most popular front-end frameworks, and it has become an essential talent for many web application development businesses. One can learn from React courses to upskill knowledge and grab job opportunities.

Why use React JS?

There are plenty of languages available that could be used for various tasks. React is preferable at present over other languages that have been in existence for a long time.

Following are some points that reason for this question:

• Speed: The speed of applications is the main objective of using React JS. It develops User Interfaces that improve the performance of the applications. It uses JavaScript object virtual DOM, which is comparatively better than the regular DOM.

• Flexibility: React JS is popular because of its simplicity and flexibility. It also provides elements that help in building creative web interfaces.

• Creation of Applications: As it requires less coding and has more functionality to offer, it becomes easier to create dynamic web applications with React.

• Components: React has multiple components that can be reused which reduces the application development time, which is a plus.

• Basic Learning: Unlike other languages, React is comparatively easy to use and get a hold of, as it uses basic HTML and JavaScript concepts. Users can learn it with a little practice and understanding.

• Debugging: The chrome extension introduced by Facebook, now Meta, has made the process of debugging React web applications so much easier.

React JS Components

A component is a building block of React because every application that will be developed with the help of React will be made of pieces called components. They make the task of building a User Interface easy and all the components can be independently worked on as they are broken down into multiple pieces. These components can later be combined into a single parent component which will be the final user interface.

The following are the two components used in React:

1. Functional Components:  These are basically JavaScript functions that can be used in React by writing JavaScript functions. The functional components are only used when we know that the user interaction or work with any other component will not be required with that particular component. 

For example –

Line 1– const Democomponent=( )=>

Line 2– {

Line 3–               return <h1>Any Message</h1>;

Line 4– }

2. Class Components: They are a little more complex than functional components. Unlike functional components, the class components can work with the other components. JavaScript ES6 can be used to make class-based components in React.

For example –

Line 1– class Democomponent extends React. Component

Line 2– { 

Line 3–    render ( ) {

Line 4–              return <h1>Any Message</h1>

Line 5–    }

Line 6– }

React JS Lifecycle

React is a collection of individual components that run according to the instructions. Every component in React has a lifecycle of its own and it is defined as the series of methods that are involved in a component’s existence. There are four lifecycle stages that a component goes through:

• Initialization: In this stage, the component is constructed and stays at the default state, it is also known as the constructor of the component. 

• Mounting: When the initialization is complete, then the component is mounted on the DOM rendered on the webpage for the first time, this stage is known as Mounting. There are two functions in the Mounting stage;

1. componentWillMount( ) function: It is invoked right before the component is mounted on the DOM.

2. componentDidMount( ) function: It is invoked right after the component is mounted on the DOM.

• Updating: When an application needs some changes then this stage comes in handy, the state of the components is updated and repainted.

• Unmounting: This is the final stage of the life cycle, as the components have to be removed from the webpage before it becomes accessible to the users.

Features of React JS

The following are the features of React JS:

• JavaScript Syntax Extension: It is a combination of HTML and JavaScript, and it provides understandable codes.

• Virtual DOM: Virtual Document Object Model is a very important feature of React JS, as it divides into modules and executes the code, and makes web applications faster as compared to real DOM.

• Performance: The virtual DOM in React JS updates only the modified parts, making the applications faster hence the performance improves.

• Extension: React has many extensions that can be used to develop user interface applications, it also supports mobile app development. 

• One-Way Data Binding: React JS follows a one-directional flow. The data is always transferred from top to bottom, that is, from the parent component to the child component.

React Concepts

React is not a framework, but a library. It was developed by Facebook, now Meta, to address specific challenges.

Here are a few core concepts of React JS:

• React JS Introduction to JSX
• React JS Rendering Elements
• ReactJS Components
• React JS Props
• React JS State in React
• React JS Lifecycle of Components
• React JS Conditional Rendering
• React JS Lists

Advantages of React JS

Here are some of the advantages of ReactJS

• It has its own Virtual DOM, which is quicker and more conventional. It also enhances the performance of applications.
• It can be used in various systems and is search engine friendly.
• Both the client and server sides are commendable, as it is quite easy to use and understand.
• It makes the entire scripting process easier as there are limited codes and not complex ones.
• React offers the availability of mobile apps which makes it versatile.
• It has advanced features and maintenance.
• It integrates various architectures and makes rendering smooth.
• React is popular among people and is supported and used by a large number of people.

Limitations of React JS

Here are some of the limitations of ReactJS: 

• It does not offer coding, which programmers may find difficult as there is only inline coding involved.
• The development pace is constantly changing and evolving.
• It also has a lack of documentation and resources may be sparse in covering the latest details.
• It can only address the application’s angle and distance.
• It can not develop a proper functional application, as that would need more tools than React JS can support.

Conclusion

Here is a quick summary of the blog: 

• React JS is a library and not a framework.
• React JS uses Virtual DOM instead of Real DOM.
• React JS simplifies the creation of complex web applications.
• React JS is a free and open-source JavaScript library.
• React JS is a combination of React and React-Dom.