Type Alias First8Chars<S, T>

First8Chars: T["length"] extends 8
    ? T extends [
        infer C1,
        infer C2,
        infer C3,
        infer C4,
        infer C5,
        infer C6,
        infer C7,
        infer C8,
        ...unknown[],
    ]
        ? `${C1 & string}${C2 & string}${C3 & string}${C4 & string}${C5 & string}${C6 & string}${C7 & string}${C8 & string}`
        : never
    : S extends `${infer Head}${infer Rest}`
        ? First8Chars<Rest, [...T, Head]>
        : never