Type Signature · #32 · 2026-05-06
What happens if you call `first([])`?
TypeScript ·Difficulty 2/3
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 first<T>(arr: [T, ...T[]]): T {
return arr[0];
}
Loading your progress...
Press 1 through 4, or tap a numbered choice, to answer. Back to hub