← Practice
Modern JavaScript·hard 30 min 120 XP

Implement Memoize

Cache a pure function's results by its arguments so repeated calls avoid repeated work.

Examples

  • const m = memoize(fn); m(2); m(2); // fn only actually runs once

Constraints

  • Keep the required function name so the tests can find it
  • Return a value instead of only logging it
  • Do not mutate inputs unless the challenge asks you to
Implement Memoize · editor

Code runs in an isolated Web Worker with a 3-second timeout — no DOM access, and it can never hang the page.