Party Time JS Fundamentals

function solve(input) {
  let guests = {
    vip: [],
    regular: []
  };
  let inParty = false;

  for (let i = 0; i < input.length; i++) {
    let current = input[i];
    if (current === "PARTY") {
      inParty = true;
      continue;
    }
    if (!inParty) {
      if (isNaN(current[0])) {
        guests.regular.push(current);
      } else {
        guests.vip.push(current);
      }
    } else {
      if (isNaN(current[0])) {
        if (guests.regular.includes(current)) {
          guests.regular.splice(guests.regular.indexOf(current), 1);
        }
      } else {
        if (guests.vip.includes(current)) {
          guests.vip.splice(guests.vip.indexOf(current), 1);
        }
      }
    }
  }

  let remainingGuestsCount = guests.vip.length + guests.regular.length;
  console.log(remainingGuestsCount);
  console.log(guests.vip.join('\n'));
  console.log(guests.regular.join('\n'));
}