Weekly challenges
One problem a week, the kind you actually hit at work. Solve it in the browser against a real test suite, earn XP toward your rank, and get your name on the list of the first to crack it.
Week 32Liveeasy
Build your own groupBy
Turn a flat array of records into an object keyed by whatever field you choose — the utility you end up rewriting on every project.
+150 XPCloses SundayOpen
Week 33Upcomingmedium
Compare two objects properly
Why does `{a:1} === {a:1}` return false? Write the deep comparison that answers what you actually meant.
+250 XPOpens MondayOpen
Week 31medium
Write debounce from scratch
Stop a function firing on every keystroke. The classic interview question, and the thing that makes search boxes usable.
+250 XPEnded 3 AugOpen
Week 30hard
Retry a request with backoff
Flaky networks are normal. Retry a failing promise a few times, waiting longer after each attempt.
+350 XPEnded 27 JulOpen