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React Deep Dive

A standalone, intermediate→advanced course on React 19. From the rendering model and reconciliation to hooks in depth, state and data flow, transitions and Suspense, Server Components and Actions, the React Compiler, and performance — taught through annotated code that shows exactly what React does and why.

Foundations & Mental Model

UI as a function of state, JSX & elements, reconciliation, and why render must be pure. Start →

Hooks In Depth

useState, useEffect (and when not to), useRef, memoization & the compiler, and custom hooks. Learn →

State Management & Data Flow

Lifting state, composition, Context, useReducer, and external stores. Manage →

Concurrent React & Suspense

Transitions, useDeferredValue, Suspense & lazy, error boundaries, and the use() hook. Go concurrent →

React 19: Actions, RSC & Forms

Server Components, Actions & useActionState, useOptimistic & forms, and the React Compiler. Level up →

Performance & Patterns

Rendering performance, memoization in practice, composition patterns, and escape hatches. Optimize →

Tooling, Testing & Production

Vite & frameworks, testing with RTL, TypeScript with React, and the production ecosystem. Ship →

The model first, then the code

Every topic starts from a model — UI = f(state), how reconciliation decides what changes, why effects synchronize with the outside world — so React stops feeling like magic and starts feeling inevitable.

React 19, verified

Written against React 19 and checked against the official docs — Actions, use(), useActionState/useOptimistic, ref-as-prop, and the React Compiler are covered as they exist today, not as they were three years ago.

Design, not just syntax

Not “here’s useEffect” but “here’s why you probably don’t need it, and what to do instead.” You’ll reason about renders, dependencies, and performance with confidence.

Diagrams that explain

The render/commit phases, reconciliation, state-as-a-snapshot, effect timing, and Suspense as theme-aware Mermaid diagrams. Bilingual (English / ไทย) with saved quiz progress.