Nathan Numerals

nathan-numerals.ts

/* Nathan's Numerals */
const NathanNumerals = [
  "•", "|", "—",
  "+", "x", "=",
  "△", "⊓", "ϟ",
  "⏥", "⧖", "⩕",
] as const;
type NathanNumeralID = typeof NathanNumerals[number];
const nanu: Record<NathanNumeralID, number> = {
  "⩕": 117147,
  "⧖": 59049,
  "⏥": 19683, 
  "ϟ": 6561,
  "⊓": 2187,
  "△": 729,
  "=": 243,
  "x": 81,
  "+": 27,
  "—": 9,
  "|": 3,
  "•": 1,
} as const;

// this function is meant to be generic
const toNumerals = <T>(
  num: number,
  numerals: T,
  numeralAccumulator: string[] = [],
) => {
  if (numerals === undefined) {
    throw new Error(
      "Numeral set undefined. A base set of numerals must be supplied",
    );
  }
  if (num < 0) {
    return toNumerals(Math.abs(num),  numerals, ["-", ...numeralAccumulator],);
  }

  const next = Object.keys(numerals).find((n) => Math.floor(num / numerals[n]));
  console.log(next, numeralAccumulator);

  if (next) {
    return toNumerals(
      num - numerals[next],
      numerals,
      [...numeralAccumulator, next],
    );
  }

  return numeralAccumulator.join("");
};

const toNanu = (num: number) => {
  // may need to add a way to reverse numeral systems
  const nu = toNumerals(num, nanu);
  return nu.split("").reverse().join("");  
}

// toNumerals<romanNumerals>(123, romanNumerals);
toNanu(152345)