Function Utility Types

function scoreGame(points: number, bonus: boolean) {
	return points + (bonus ? 10 : 0)
}

type ScoreResult = ReturnType<typeof scoreGame>
type ScoreArgs = Parameters<typeof scoreGame>

• ReturnType<T> - Get the return type of a function
• Parameters<T> - Get parameter types as a tuple
• Awaited<T> - Unwrap Promise types

1. Use ReturnType to extract a function's return type
2. Use Parameters to get a function's parameter types
3. Use Awaited to unwrap Promise types
4. Create a wrapper function that preserves types