Ever hit a wall when a list grows to thousands of rows and React starts to choke? Mounting 10,000 DOM nodes at once is the problem — rendering only what fits on screen is the fix. 🧩 Overview Build a virtualized list of 10,000 contacts that mounts only the rows visible in the scroll viewport (plus a small overscan), using fixed row heights and windowing math. 👉 https://www.reactchallenges.com/challenges/virtualized-list ✅ Requirements Render a virtuali...