How React Works

React is a JavaScript library for building user interfaces, primarily for single-page applications where the user interacts with the application without reloading the page. It was developed by Facebook and is widely used for building modern web applications.

Here's a simplified overview of how React works:

Components:

React applications are built using components. Components are the building blocks of a React application, representing different parts of the user interface. Components can be simple, representing a button or a form, or they can be more complex, representing an entire page or application.

Virtual DOM:

React uses a virtual DOM to efficiently update the user interface. The virtual DOM is a lightweight copy of the real DOM (Document Object Model) that React keeps in memory. When the state of a component changes, React first updates the virtual DOM rather than the actual DOM.

Reconciliation:

React uses a process called reconciliation to determine the difference between the current virtual DOM and the previous one. It calculates the most efficient way to update the actual DOM to match the updated virtual DOM.

Render:

When a component's state or props change, React re-renders the component and updates the virtual DOM. React then compares the new virtual DOM with the previous one and calculates the minimal number of changes needed to update the actual DOM.

Updating the DOM:

React applies the calculated changes to the real DOM, updating only the parts of the DOM that have changed. This approach minimizes the number of manipulations on the actual DOM, which is a costly operation, and improves the overall performance of the application.

One-way Data Binding:

React follows a one-way data flow. Data flows in a single direction, from the parent component to child components. This helps maintain a predictable state in the application.

JSX (JavaScript XML):

React uses JSX, which is a syntax extension for JavaScript. JSX allows you to write HTML-like code in your JavaScript files, making it easier to describe what the UI should look like.