day2.ts

/*Solution*/
type CookieSurveyInput<T> = keyof T;

/*Tests*/
import { Expect, Equal } from "type-testing";

const cookieInventory = {
	chocolate: 1,
	sugar: 20,
	gingerBread: 10,
	peanutButter: 30,
	snickeDoodle: 73,
}
type test_cookies_actual = CookieSurveyInput<typeof cookieInventory>;
//   ^?
type test_cookies_expected = "chocolate" | "sugar" | "gingerBread" | "peanutButter" | "snickeDoodle";
type test_cookies = Expect<
	Equal<
		test_cookies_actual,
		test_cookies_expected
	>
>;

const unrelated = {
	hi: 1,
	hi2: 1,
	hi3: 1,
	hi4: 1,
	hi5: 1,
	hi6: 1,
	hi7: 1,
}
type test_unrelated_actual = CookieSurveyInput<typeof unrelated>;
//   ^?
type test_unrealted_expected = "hi" | "hi2" | "hi3" | "hi4" | "hi5" | "hi6" | "hi7"
type test_unrelated = Expect<
	Equal<test_unrelated_actual, test_unrealted_expected>
>;