This repository is a comprehensive React training workshop containing three distinct demo applications: a client‑side SPA using React Router, a server‑side rendered app using the React Router framework (with loaders/actions), and a Next.js 14 App Router example. It provides progressive lessons covering core concepts (components, state, routing, forms, hooks, data fetching), advanced patterns (compound components, form abstractions, optimistic UI, imperative React), and testing with Vitest and React Testing Library. The architecture is educational: each app demonstrates different React ecosystem approaches, with mock data served by json‑server, authentication via cookie sessions, and state management through context providers. External dependencies include React 18/19, React Router v7, Next.js 14, Tailwind CSS, bcrypt, and TanStack Query. The codebase is well‑structured for learning, with lecture code, practice exercises, and final solutions organized by lesson.