gistfile1.js

"use strict";

function test() {
  let arr = ["a", "b", "c", "d", "e", "f"];
  let result = [];
  while (arr.length) {
    let i = Math.floor(Math.random() * (arr.length - 1));
    result.push(arr.splice(i, 1)[0]);
  }
  return result;
}

let result = {
  a: [0, 0, 0, 0, 0, 0],
  b: [0, 0, 0, 0, 0, 0],
  c: [0, 0, 0, 0, 0, 0],
  d: [0, 0, 0, 0, 0, 0],
  e: [0, 0, 0, 0, 0, 0],
  f: [0, 0, 0, 0, 0, 0]
};
for (let i = 0; i < 1000000; i++) {
  let items = test();
  for (let rank = 0; rank < items.length; rank++) {
    result[items[rank]][rank]++;
  }
}
console.log(result);