Public JavaScript challenges shared by the EraCode community. These pages are teasers — skill maintenance starts when you attempt the full problem inside EraCode.
Practice a small JavaScript accessibility pattern: move keyboard focus to an error summary after validation so screen reader and keyboard users get immediate context.
Quick check-in on JavaScript testing: understand when to use a spy and implement a tiny Jest assertion to verify call arguments.
Quick practice on JavaScript data structures: using Map for frequency counting, plus a short concept check.