Lesson 9: useEffect and Fetching Data in React: Loading, Errors, Cleanup and Race Conditions

Connect React to a real ASP.NET Core API. Learn useEffect properly, its dependencies and cleanup, and fetch data the right way with loading states, errors, debouncing and no race conditions. In this lesson (Lesson 9 of 20 in the "React JS: Beginner to Advanced" course) you will learn: What side effects are, and when NOT to use useEffect Effect, dependencies and cleanup The lifecycle of an effect and StrictMode's double run Loading, error and success states fetch with AbortController Debounced search and avoiding race conditions The most common useEffect mistakes YOUR TASK: Fetch users from jsonplaceholder, show loading and error states, and add a debounced search. ------------------------------------------ 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 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 #useEffect #ReactHooks #API #ReactJS #JavaScript