React Tutorial

Understand React as a UI library, its declarative model, and why teams choose it for modern web apps.

Learn the core React idea: your UI is a function of state, and re-renders follow data changes.

Create a modern React project with Vite, understand the folder structure, and run your first dev server.

Master JSX syntax: expressions, attributes, rules, and how it compiles to JavaScript.

Build reusable UI with function components, exports, and component composition basics.

Pass read-only data from parent to child with props and understand one-way data flow.

Use the children prop and composition patterns to build flexible layout components.

Show different UI with if/return, ternaries, logical AND, and switch patterns.

Render collections with map, choose stable keys, and avoid common list rendering bugs.

Master useState: initial state, functional updates, batching, and multiple state variables.

Update objects and arrays in state correctly by creating new values instead of mutating.

Handle user interactions with synthetic events, handler patterns, and passing arguments.

Build forms where React state is the single source of truth for every field value.

Apply styles with className, CSS files, and CSS Modules for scoped component styles.

Break UIs into component trees, identify state, and decide where data should live.

Inspect component trees, props, state, and re-renders using React Developer Tools.

Build a complete todo list app applying components, state, events, lists, and immutable updates.

Build a polished profile card with props, composition, conditional UI, and CSS Modules.

Learn what useEffect does, when to use it, and how it differs from rendering logic.

Master the dependency array, exhaustive-deps rules, and avoiding infinite effect loops.

Write correct cleanup functions and understand stale closures in effects and event handlers.

Implement robust data fetching with useEffect, handle race conditions, and structure API calls.

Model async UI states explicitly and build polished loading, error, and empty experiences.

Extract reusable stateful logic into custom hooks that compose built-in hooks.

Use useRef for DOM nodes, imperative focus, and mutable values that do not trigger re-renders.

Manage complex state transitions with reducers, actions, and dispatch.

Share theme, auth, and locale data across the tree without prop drilling.

Combine useReducer with Context for predictable global state without external libraries.

Decide where state belongs as features grow and avoid premature global state.

Set up client-side routing with React Router, map URLs to components, and structure a multi-page SPA.

Build layouts with Outlet, navigate with Link and NavLink, and read dynamic URL parameters.

Code-split routes and components to reduce initial bundle size and improve load time.

Validate forms in React, understand key remounting behavior, and render modals with portals.

Build a notes app combining routing, context, reducer, effects, and localStorage persistence.

Apply useMemo and useCallback correctly for expensive calculations and stable references.

Skip re-renders of pure components when props are shallowly equal.

Keep the UI responsive during expensive updates with React concurrent features.

Use React DevTools Profiler and browser tools to find and fix real bottlenecks.

Catch render errors and show fallback UI so one broken widget does not crash the app.

Build inclusive UIs with semantic HTML, ARIA, keyboard support, and focus management.

Write user-centric component tests with Vitest, React Testing Library, and user-event.

Type components, props, events, hooks, and context for safer React codebases.

Design flexible APIs with compound components, render props, and controlled/uncontrolled patterns.

Recognize when Context is not enough and evaluate lightweight stores and data libraries.

Organize growing codebases by feature, enforce boundaries, and keep components maintainable.

Understand Suspense for data fetching, streaming, and how frameworks integrate async UI.

Build an InTelleX-style lesson player with sidebar curriculum, content pane, progress, and locks.

Production checklist: performance, accessibility, error handling, build, and static deploy.

Bridge from client React to Next.js: routing, server components, data fetching, and deployment.