Code RoomInfinite scroll feed with dedup
MediumPrep Room Coding #4360

Infinite scroll feed with dedup

Vibe & agenticDatabases & SQLNetworking & APIsMid–Senior~16 min

You're building an infinite-scroll feed in a React/TypeScript app on top of a cursor-paginated API, using TanStack Query's `useInfiniteQuery`. You want an AI agent to write the data-fetching hook and the merge/dedup logic. Write the prompt/spec — constraints, edge cases, acceptance criteria — for a first-try-correct result. What does a casual prompt ("add infinite scroll to the feed") get wrong on the client side?

Implement
merge_cursor_pages(pages: list[list[str]]) → list[str]
Examples
in[[["c2","a","b"],["","b","c"]]]out["a","b","c"]
in[[["c2","a"],["c3","b"],["","c"]]]out["a","b","c"]
in[[["","x"],["c9","y"]]]out["x"]
What a strong answer looks like

Treat the AI’s output as a draft to verify, not an answer to trust. Name the specific flaw and the input that triggers it, say how you’d catch it (tests, edge cases, reading critically), and how you’d re-prompt or decompose to get it right.

0:00 of about 16 min

Vibe & agentic: describe the solution in plain language (or narrate it) and the coach grades your approach.

Which questions mattered is sealed until you submit. Telling you now would just be handing over the edge cases.