Skip to main content

Type Signature · #24 · 2026-04-28

What happens when you try to compile this?

TypeScript ·Difficulty 1/3

How to play

Read the TypeScript snippet and pick the correct type from four choices. Think about inference, narrowing, and utility types. Press 1–4 or click to answer.

function f(arr: readonly number[]) {
  return arr.sort();
}

Loading your progress...

Press 1 through 4, or tap a numbered choice, to answer. Back to hub