Performance optimization reduces load times and improves user experience. I use code splitting to break bundles into smaller chunks loaded on demand. React's lazy() and Suspense enable component-level code splitting. Dynamic import() loads modules asy

State management solutions handle data flow in complex applications. I use React Context API for moderate state sharing without prop drilling. The createContext function creates context objects, while Provider passes data down the tree. The useReducer

React Hooks enable state and lifecycle features in function components. I use useState to add stateful values that persist between renders. The useEffect hook handles side effects like data fetching, subscriptions, and DOM manipulation. Dependencies a

JavaScript classes provide syntactic sugar over prototype-based inheritance using class keyword. I define constructors with constructor() method for initialization. Using extends creates subclasses that inherit from parent classes. The super keyword c

ES6 modules organize code into separate files with export and import statements. I use export default for single main export and export { name } for named exports. The import { name } from './module.js' syntax imports specific exports. Using import *

JavaScript error handling uses try...catch...finally blocks to manage exceptions gracefully. I throw custom errors with throw new Error('message') for better debugging. The finally block runs regardless of success or failure. Using console.error(), co

The Fetch API provides modern interface for HTTP requests returning promises. I use fetch(url) to make GET requests that resolve with Response objects. The response.json() parses JSON data asynchronously. POST requests need method, headers, and body o

DOM manipulation modifies HTML structure using JavaScript methods like createElement(), appendChild(), and removeChild(). I minimize reflows by batching DOM changes together. Using DocumentFragment groups multiple changes before inserting into DOM. Th

Event listeners attach handlers to DOM elements using addEventListener(). I specify event type like click, input, submit with handler function. The event object contains information about the triggered event. Using event.preventDefault() stops default

ES6 destructuring extracts values from arrays and objects with concise syntax. I use const [a, b] = array for array destructuring and const {name, age} = obj for objects. The spread operator ... expands iterables in arrays, objects, and function argum

Array methods enable functional programming patterns in JavaScript. The .map() method transforms each element and returns new array. I use .filter() to create arrays with elements meeting criteria. The .reduce() method accumulates values into single r

Promises represent eventual completion or failure of asynchronous operations. I create promises with new Promise((resolve, reject) => {}) executor function. The .then() method chains successful results while .catch() handles errors. Using .finally(