Map()

const animal = new Map()

animal.set("rabbit",10);
animal.get("rabbit");
animal.get("dddd");

sid=> 개인룸
const sids = new Map();
sids.set("a",true);
sids.set("b",true);

rooms=> 개인룸.공개룸
const rooms = new Map();
rooms.set("a",true);
rooms.set("b",true);
rooms.set("c",true);

rooms.forEach((value,key)=>console.log(value,key))

공개룸 찾기
rooms.forEach((_,key)=>{
if(sids.get(key) === undefined){
console.log(key)
}
})