React Fundamentals

Why it matters

React is the de facto UI library for building modern web apps. Mastering components, props, and hooks lets you ship reliable interfaces quickly.

Core steps

• Start with function components and props to break down UI.
• Use useState and useEffect for local state and side effects.
• Lean on composition over inheritance for reusable patterns.
• Fetch data with suspense-ready patterns or a simple data hook.

Quick example

function Counter() {
  const [count, setCount] = useState(0);
  return (
    <button onClick={() => setCount((c) => c + 1)}>
      Count {count}
    </button>
  );
}

Tips

• Co-locate state where it is used.
• Prefer controlled inputs for forms.
• Keep effects idempotent and scoped.