date: 2025-08-17 topics: [nextjs, authentication, state-management, tanstack-query, bff-pattern] day: 30

Day 30 – NextAuth Fixes, BFF API & TanStack Query

✅ What I Worked On

Fixed session null and token type issues in NextAuth
Implemented BFF (Backend For Frontend) layer with Next.js API routes for feed & like/dislike
Added optimistic UI updates for smoother UX
Standardized error and response handling in API calls
Explored TanStack Query for caching and state management in feed actions

📚 What I Learned

Handling optional session safely in NextAuth
Why BFF is the industry standard to separate frontend logic from backend APIs
How to implement optimistic UI updates for like/dislike actions
TanStack Query for fetching, caching, and mutations

❌ Blockers

Still need to finalize whether to keep all API call logic inside Next.js API routes or directly in frontend with TanStack Query
Need deeper practice in TanStack Query patterns (cache invalidation, refetch vs optimistic updates)

🧠 Reflection

Today felt like a big step in professionalizing the frontend architecture — moving away from ad-hoc fetches towards BFF + query caching.
I can already see how this will scale much better as the project grows.

Next step: go deeper into TanStack Query and fully migrate feed + like/dislike into its flow.