JavaScript Challenge

Feed your brain. Level up. Learn to write real JavaScript by solving one puzzle at a time, right on your phone. JavaScript Challenge is a single path of original coding problems, from your first function to graphs, dynamic programming and beyond. Every solution runs on-device in real JavaScript and is checked against hidden tests, so passing means it actually works. One purchase, everything included: every challenge ships with the app. No subscription, no in-app purchases, no ads, no account. WRITE REAL CODE • A coder keyboard built for JavaScript: tab, brackets, quotes, snippets, undo • Instant feedback with named tests, expected vs actual output • Some levels enforce rules (no built-in array helpers, recursion required) so you learn the technique, not the shortcut LEARN THE RIGHT WAY • Three-tier hints from Rhino, your smug but surprisingly helpful mentor • Curated solutions after you…