04. Party Time-Associative Arrays - Exercise

function partyTime(arr) {
    let guestList = new Set(arr.slice(0, arr.indexOf('PARTY')));
    let attendingGuests = new Set(arr.slice(arr.indexOf('PARTY') + 1));

    for (let guest of attendingGuests) {
        if (guestList.has(guest)) {
            guestList.delete(guest);
        }
    }

    console.log(guestList.size);
    // let remainingGuests = [...guestList];
    // console.log(remainingGuests.join('\n'));
    console.log(Array.from(guestList).join('\n'));
}