Map an array to multiple values (fixed or random)

mapMulti.ts

const randomize = (min: number, max: number) =>
  Math.floor(Math.random() * (max - min + 1)) + min;

export const mapMulti = (val1: number, val2?: number) => {
  let iterator: () => unknown[];
  if (typeof val2 === "undefined") {
    const arr = Array.from({ length: val1 });
    iterator = () => arr;
  } else {
    iterator = () => Array.from({ length: randomize(val1, val2) });
  }

  return function <T, U>(
    array: T[],
    fn: (x: T, index: number, gIndex: number) => U
  ) {
    const result: U[] = [];
    array.forEach((x, gIndex) => {
      iterator().forEach((_, index) => result.push(fn(x, index, gIndex)));
    });
    return result;
  };
};