10 Core concepts you should know about React.js

Today I’m Talking about React core concept. Before you begin, please note that this is a beginner-friendly guide that covers the concepts I classify as Fundamentals for working with React. It is not a complete guide to React but rather a complete introduction.

1. What is React?

React is an open-source JavaScript library (not a framework) that creates user interfaces(UIs) in a predictable and efficient way using declarative code. You can use it to help build single-page applications and mobile apps, or to build complex apps if you utilize it with other libraries.

2. How React works?

At its very core, React basically maintains a tree for you. This tree is able to
do efficient diff computations on the nodes.

Think of your HTML code as a tree. In fact, that is exactly how the browser treats your DOM (your rendered HTML on the browser). React allows you to effectively reconstruct your DOM in javascript and push only those changes to the DOM which have actually occurred.

3. JSX is syntactic sugar

JSX is a core thing of react.js. You can say it is the heart of React. There is nothing like JSX -neither to the JavaScript nor to the browser. JSX is a very common thing to creating a very specific JavaScript object.

4. React DOM

When React was released, There was a lot of buzz about its performance because it starts a new idea for virtual DOM that can be used to resolve differences between actual DOM.

DOM is (Document Object Model). It’s the browser’s programming interface for XML and HTML. It makes a tree structure. The DOM API can be used to change a document structure, style, and component.
Although React performance is the most important reason why it is extremely popular today. I think React was a game-changer because it created a common language between developers and browsers that allows developers to declaratively describe UIs and manage actions on their state instead of actions on their DOM elements.