Introduction

ReactJS is a component-based JavaScript library used to build dynamic and interactive user interfaces. It simplifies the creation of single-page applications (SPAs) with a focus on performance and maintainability.

What is React?

• React is a front-end JavaScript library.

• React was developed by the Facebook Software Engineer Jordan Walke.

• React is also known as React.js or ReactJS.

• React is a tool for building UI components.

How does React Work?

• React creates a VIRTUAL DOM in memory.

• Instead of manipulating the browser's DOM directly, React creates a virtual DOM in memory, where it does all the necessary manipulating, before making the changes in the browser DOM.

• React only changes what needs to be changed!

• React finds out what changes have been made, and changes only what needs to be changed.

• You will learn the various aspects of how React does this in the rest of this tutorial.

What You Should Already Know

Before you continue you should have a basic understanding of the following:

• HTML

• CSS

• JAVA SCRIPT
  

Difference between a Library and Framework

A library is a collection of pre-written code that you can use when needed.

A framework provides a complete structure for building applications.

Importance of React

Before React, front-end development struggled with:

• Manual DOM Manipulation: Traditional JavaScript directly modified the DOM, slowing down the performance.

• Complex State Management: Maintaining UI state became messy and hard to debug.

• Tight Coupling in Frameworks: Frameworks like Angular introduced complex two-way data binding that made code harder to manage.

React solved these issues with a modern and modular approach.

Core Features

• Virtual DOM: React updates only the changed parts of the DOM, resulting in faster rendering.

• One-Way Data Binding: Ensures predictable and easy to debug data flow.

• Component-Based Architecture: Breaks UI into reusable pieces, improving the code reusability and scalability.