Learn ReactJS Basics: A Guide for Beginners

"Welcome to my beginner's guide to ReactJS! In this series of articles, we'll explore the fundamental concepts of this powerful frontend library, from the basics to advanced optimization techniques. If you're new to ReactJS, this guide is the perfect place to start. We'll cover everything you need to know to create interactive user interfaces using ReactJS's declarative approach. So, let's dive in and get started!"

ReactJS is a powerful front-end library that enables the creation of interactive user interfaces using a declarative approach. Unlike a full-fledged framework, ReactJS is easy to learn and not overly opinionated. By using reusable components, ReactJS significantly reduces code management costs. Additionally, ReactJS employs a virtual DOM, which makes it more efficient than using a real DOM.

Benefits of using ReactJS

Reusable Components: React allows to make of reusable components. In React there code management is very less expensive. For example, every web app has similar two or three types of buttons so we don't have to create a button component many times it can be used multiple times. Here's an example code snippet for a simple button component:
```
  import React from 'react';

  const Button = ({ onClick, variant = 'primary', children }) => {
    const className = `btn btn-${variant}`;
    return (
      <button className={className} onClick={onClick}>
        {children}
      </button>
    );
  }

  export default Button;
```
In this code snippet, we define the Button component that accepts three props:
- onClick: a function to handle click events
- variant: a string representing the style theme of the button, defaulting to primary
- children: the content inside the button
  
  We use the destructuring assignment syntax to extract these props from the props object passed into the component. We define a variable className that concatenates the btn class with the variant prop to set the button style CSS class.
  
  Finally, we render a <button> element with the className and onClick props set, and render the children inside the button.
  
  You can now use this Button component in any of your applications by importing it and passing in the required props.
Virtual Dom: React uses a virtual DOM instead of a real DOM because repainting the real DOM is more expensive. The virtual DOM compares the original state to an update in a specific component where the data has changed, eliminating the need to repaint the entire page. We will cover this topic in more detail in future blogs.
Large community support: ReactJS boasts a vibrant and supportive community that offers extensive documentation, a plethora of third-party tools, and libraries catering to all your needs. With ReactJS, you can tap into a vast pool of resources that make development a breeze.
Cross-platform development: ReactJS allows developers to build applications that can be used on various platforms, including web, mobile (using React Native), and desktop (with Electron).

How does it work?

One key thing to keep in mind is that React only updates the DOM nodes if there is a difference between the previous and new virtual DOMs. Otherwise, it won't touch the DOM.

Overall, this process allows React to update the user interface very quickly and efficiently, avoiding unnecessary and computationally expensive operations.

If you are still not able to visualise the ReactJS concept https://react.gg/visualized follow this link it will help you a lot.

Thank you😃 for reading.