Alex-o-Meter

bookmarklet.js

(function () {
  let elementGroups = document.querySelectorAll("div.VfPpkd-aGsRMb");
  // console.log(elementGroups);

  if (elementGroups.length == 0) {
    alert("Error: cannot detect participant groups.\n\nOpen the people sidebar and try again. If it still doesn't work, check changes in CSS media queries.");
    return;
  }

  let namesOnline = new Array();
  elementGroups[0].querySelectorAll("div.VfPpkd-aGsRMb span.zWGUib").forEach((e) => { namesOnline.push(e.innerText); }); 
  // console.log(namesOnline);

  let namesOffline = new Array();
  if (elementGroups[1] !== undefined) {
    elementGroups[1].querySelectorAll("div.VfPpkd-aGsRMb span.zWGUib").forEach((e) => { namesOffline.push(e.innerText); });
  }
  // console.log(namesOffline);	

  let nameFilterFunc = (name) => {
    const namePrefixes = [
      "Alex",
      "Aliaksa",
      "Oleksa",
      "Aleks"
    ];
    let nameParts = name.split(" ");

    return namePrefixes.find((prefix) => { return nameParts[0].startsWith(prefix); }) !== undefined;
  };

  let alexesOnline = new Array();
  alexesOnline = namesOnline.filter(nameFilterFunc);
  // console.log(alexesOnline);

  let alexesOffline = new Array();
  alexesOffline = namesOffline.filter(nameFilterFunc);
  // console.log(alexesOffline);
	
  let alexesOnlineRate = Math.floor(alexesOnline.length/namesOnline.length * 100);
  // console.log(alexesOnlineRate);

  if ((alexesOnline.length + alexesOffline.length) > 0) {
    alert(`Alex-o-Meter\n\nOut of ${namesOnline.length} online people ${alexesOnlineRate}% are Alexes.`);
  } else {
    alert("This meeting is Alex free. Next time consider to invite at least one Alex!");
  }
}());

A nice service to generate a bookmarklet: https://make-bookmarklets.com/.