taytwkim/mern-task-manager ? reverse-engineered prompt

Build me a simple MERN task manager app that helps me learn how the backend and frontend fit together.

I want a small CRUD app where I can add a task, see all tasks, edit a task title or mark it complete, and delete a task. Keep it beginner friendly and easy to debug, since I’m using this to practice for a coding interview and I’m still getting comfortable with JavaScript.

Please work step by step, and explain what each part is doing as you go, especially the Express routes, Mongoose model, React components, state, and API calls. If you need to, look up current docs online so the code matches modern best practices.

I’d also like you to help me understand errors instead of just rewriting everything. When something breaks, point me to the likely cause and show me how to trace the data flow from the React UI to the API to MongoDB. Keep the app simple and focused on learning rather than fancy features.