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Type Signature · #44 · 2026-05-18

What is type `R`?

TypeScript ·Difficulty 3/3

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 create(x: string): string;
function create(x: number, y: number): number;
function create(x: any, y?: any) { return x; }
type R = Parameters<typeof create>;

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