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. Create NewUser from createUser's return type
2. Create CreateUserParams from createUser's parameters
3. Create FetchUserResult as the resolved value of fetchUser (unwrap the Promise)
4. Create ProcessDataArgs from processData's parameters
5. Create loggedCreateUser that:
   • Accepts the same parameters as createUser
   • Returns the same shape as createUser
   • Can log the args, then call createUser
6. Export loggedCreateUser