Atharv Gyan

Variables 1. Declaration var Historically, variables were declared using the var keyword. However, it has some scoping issues and is generally replaced by let and const in modern JavaScript. javascript var x = 10; let Introduced in ES6, let allows you to declare block-scoped variables. This means the variable is only available within the block it is defined. javascript let y = 20; const Also introduced in ES6, const is used to declare block-scoped variables that are read-only. Once a value is assigned to a const variable, it cannot be reassigned. javascript const z = 30; 2. Variable Scope Global Scope: Variables declared outside of any function or block are in the global scope and can be accessed from anywhere in the code. Function Scope: Variables declared within a function using var are confined to the function scope. Block Scope: Variables declared with let or const within a block (denoted by {}) are confined to that block. javascript if (true) {   var a = 40;  // global scope (if

In the dynamic landscape of web development, React has emerged as a game-changer, empowering developers to create interactive and efficient user interfaces. This comprehensive guide will take you on a journey through the fundamentals of React, providing hands-on examples to solidify your understanding. Understanding the Basics What is React? React is a JavaScript library for building user interfaces, developed by Facebook. It allows developers to create reusable UI components, making it easier to manage complex interfaces and maintain a structured codebase. Setting Up Your React Environment To get started with React, you'll need Node.js and npm installed on your machine. Create a new React app using: npx create-react-app my-react-app cd my-react-app npm start Components and Props Components in React Components are the building blocks of React applications. They can be functional or class-based, representing different parts of the UI. Let's create a simple functional component: