Lesson 15: TanStack Query (React Query) Tutorial: Caching, Mutations and Optimistic Updates

Replace pages of useEffect code with TanStack Query: caching, background refetching, pagination, mutations and optimistic updates, against a real ASP.NET Core API. In this lesson (Lesson 15 of 20 in the "React JS: Beginner to Advanced" course) you will learn: Client state vs server state QueryClient setup and the devtools useQuery and query key design staleTime and how the cache refreshes useMutation and invalidateQueries Optimistic delete with rollback Common TanStack Query mistakes YOUR TASK: Add a details panel with useProduct(id) and prefetch details on row hover. ------------------------------------------ ABOUT THIS COURSE "React JS: From Beginner to Advanced" is a free, step-by-step video course that takes you from your first component to full-stack, production-ready apps. 20 lessons and 5 real-world projects with React 19, Vite, React Router, TanStack Query, Zustand, Redux Toolkit, React Hook Form, Zod, Tailwind CSS, TypeScript, Vitest, and an ASP.NET Core Web API (.NET 10) back end with JWT and SignalR. Full course playlist:    • React JS Full Course: Beginner to Advanced...   previous Lession 13    • Lesson 13: React Hooks in Depth: useRef, u...   Lession 12    • Lesson 12: React Global State: Context, us...   Lession 11    • Lesson 11: React Router Tutorial: Routes, ...   Lession 9    • Lesson 9: useEffect and Fetching Data in R...   Lession 8    • Lesson 8: React Forms and Validation: Cont...   Lession 7    • Lesson 7: Lists, Keys and Conditional Rend...   Lession 6    • Lesson 6: React useState and Events: Re-re...   Lession 5    • Lesson 5: React Props Explained: Passing D...   Lession 4    • Lesson 4: JSX and Components in React: Rul...   Lession 3    • Lesson 3: React Setup with Vite: Node.js, ...   Lession 2    • Lesson 2: Modern JavaScript for React: Arr...   Lession 1    • Lesson 1: What is React? Components, SPAs ...   AI in asp.net core Full Course Video link English and Hindi English version:    • AI with ASP.NET Core: Full Course for C# D...   Hindi playlist:    • AI with ASP.NET Core Hindi में | C# Develo...   Subscribe for the next lesson, and tell me in the comments what you are building with React! #React #TanStackQuery #ReactQuery #ReactJS #API #Frontend