Osu! beatmap play occurence

let uid = document.location.href.substring(25);
let totalBMs = document.querySelector("div.user-profile-pages.ui-sortable > div:nth-child(4) > div > h3:nth-child(4) > span").textContent;
async function getBMs(uid) {
  let a = await fetch(`https://osu.ppy.sh/users/${uid}/beatmapsets/most_played?offset=1&limit=${totalBMs}`, {
    "credentials": "include",
    "headers": {
      "User-Agent": "Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:84.0) Gecko/20100101 Firefox/84.0",
      "Accept": "*/*",
      "Accept-Language": "en-US,en;q=0.5",
      "X-CSRF-Token": "uy3Ba5IyVV5EITQHqiq3DNnlll9CEBRM2iVmmdKY",
      "X-Requested-With": "XMLHttpRequest",
      "Sec-GPC": "1"
    },
    "referrer": `https://osu.ppy.sh/users/${uid}`,
    "method": "GET",
    "mode": "cors"
  });
  let b = await a.json();
  return(b);
};

function foo(arr) {
  var a = [],
    b = [],
    prev;

  arr.sort();
  for (var i = 0; i < arr.length; i++) {
    if (arr[i].count !== prev) {
      a.push(arr[i].count);
      b.push(1);
    } else {
      b[b.length - 1]++;
    }
    prev = arr[i].count;
  }

  return [a, b];
}

let info = await getBMs(uid);
let result = foo(info);
console.log('[' + result[0] + ']', '[' + result[1] + ']')