Calculating frequency

freq.js

let nums = [30, 36, 37, 41, 42, 41, 40, 41, 46, 47, 46, 46, 47, 45, 46, 45, 50, 51, 50, 52, 52, 51, 51, 52, 50, 50, 56, 55, 56, 57, 57, 57, 57, 58, 58, 55, 61, 62, 67, 67];
let unique = _.unique(nums);
let absoluteFrequency = _.countBy(nums, num => num);
let relativeFrequency = () => {
  let obj = {};
  let values = _.values(absoluteFrequency);
  let keys = _.keys(absoluteFrequency);
  for (var i = 0; i < keys.length; i++) {
    obj[keys[i]] = values[i] / nums.length;
  }
  return obj;
}
let cummulativeFrequency = _.values(absoluteFrequency).reduce((sum, val) => sum += val, 0);
unique.sort();
console.log(`Уникальные числа: ${unique}`);
console.log(`Относительная частота: `, relativeFrequency());
console.log(`Абсолютная частота: `, absoluteFrequency);
console.log(`Накопительная частота: ${cummulativeFrequency}`);