usingReduceClosure.js

// More advanced application using closures and pure functions
const randomNum = n => Math.floor(Math.random() * n);


const fillRandomArray = (len, range) => Array.from({length: len}, () => randomNum(range))

const sorterCreator = (length, ceiling) => {
  const buckets = {
    low: 0,
    mid: 0,
    high: 0,
  }
  // create a random array of integers in interval from [0, ceiling)
  const randomArray = fillRandomArray(length, ceiling);
  // sorting callback for reduce
  const sortingHat = (obj, num) => {
    if (num < Math.floor(ceiling / 3)) {
      obj.low++
    } else if (num < Math.floor(ceiling / 3) * 2) {
      obj.mid++
    } else {
      obj.high++
    }
    // uncomment to see accumulator status at every step
    // console.log(`current accumulator status: ${JSON.stringify(acc)}`);
    return obj
  }

  return () => randomArray.reduce(sortingHat, buckets);
}