BitWithBite
React · Quick Reference
Lesson 1 — What is React Cheat Sheet
In one line: React lets you declare what the UI should look like; it handles updating the actual DOM for you.
Core Concepts
1Component. A reusable UI piece.
2Props. Data passed INTO a component.
3State. Data that changes INSIDE a component.
4Hook. A function to use React features.
5Virtual DOM. Fast in-memory copy of the real DOM.
Vanilla vs React
// Vanilla JS
document.getElementById("count").textContent = count;
// React
function Counter() {
const [count, setCount] = useState(0);
return <button onClick={() => setCount(c=>c+1)}>{count}</button>;
}