Question 1

Build Infinite Scroll with IntersectionObserver & Skeleton

Accepted Answer

**Target Audience:** React developers who have built (or read) [infinite scroll with a scroll listener](/interview-question/build-infinite-scroll) and want the IntersectionObserver version with skeleton loading cards. **Difficulty:** Medium > **How to read this doc:** Plain language first, then 📌 Interview term: callouts. The Verified section has two parts. In jsdom, which has no IntersectionObserver, the driver installed a small stub and decided by hand when the sentinel was visi

Question 2

Build a Job Board (paginated fetch)

Accepted Answer

**Target Audience:** Developers preparing for a frontend machine coding round who know useState and useEffect and want to handle a two-step paginated fetch with loading, errors and retries properly. **Difficulty:** Medium > **How to read this doc:** Plain language first, then 📌 Interview term: callouts. Code excerpts are copied from the runnable solution, and the Verified section quotes what it printed on React 19.3.1. The Hacker News API is **simulated**

Question 3

Build Infinite Scroll

Accepted Answer

**Target Audience:** React developers new to infinite scrolling who know useState and useEffect and want to build it from first principles with a scroll listener. **Difficulty:** Medium > **How to read this doc:** Plain language first, then 📌 Interview term: callouts. The Verified output was produced by running the solution on React 19.3.1 under StrictMode in jsdom, with the scroll container given a fixed clientHeight and a content-based

FRONTEND MACHINE CODINGDECODED.

Medium

Build Infinite Scroll with IntersectionObserver & Skeleton

Build a Job Board (paginated fetch)

Build Infinite Scroll