15 - Last of Array

// Extracts the last element by splitting the tuple into:
// Rest = all elements except last
// Last = final element
type Last<T extends unknown[]> =
    T extends [...infer Rest, infer Last]
        ? Last
        : never;


// Adds a dummy `never` at the beginning,
// then uses the original tuple length as an index.
// That shifted index points to the last element.
type Last<T extends unknown[]> =
    [never, ...T][T["length"]];