BuildTupleDigitByDigit

type BuildTupleDigitByDigit<
    Length extends string,
    Fill,
    Accumulator extends UnknownArray = []
> = Length extends `${infer First extends DigitCharacter}${infer Rest}`
    ? BuildTupleDigitByDigit<
          Rest,
          Fill,
          [...RepeatTupleTenTimes<Accumulator>, ...DigitTupleOf<First, Fill>]
      >
    : Accumulator;

type BuildTupleDigitByDigit<
    Length extends string,
    Fill,
    Accumulator extends UnknownArray = []
> = Length extends `${infer First extends DigitCharacter}${infer Rest}`
    ? BuildTupleDigitByDigit<
          Rest,
          Fill,
          [...RepeatTupleTenTimes<Accumulator>, ...DigitTupleOf<First, Fill>]
      >
    : Accumulator;