Alex Chang

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(

Closures allow functions to access variables from outer scopes even after outer function returns. I create closures when inner functions reference outer function variables. Lexical scope means functions look up variables where they're defined, not whe

BEM (Block Element Modifier) naming uses .block__element--modifier pattern for scalable CSS. I define blocks as independent components like .card. Elements within blocks use .card__title and .card__body. Modifiers indicate variations with .card--featu

Container queries enable responsive components based on container size using @container at-rule. I set container-type: inline-size to create query containers. The @container (min-width: 400px) queries container width instead of viewport. Named contain