프로그래머스 | 오픈채팅방

function solution(record) {
    var answer = [];
    let obj={};
    for (let i=0;i<record.length;i++){
        let [state, id, nick]=record[i].split(' ');
        if(state==='Enter'){
            if(id in obj){
                obj[id]=nick;
            }else{
                obj[id]=nick;
            }
        }else if(state==='Change'){
            obj[id]=nick;
        }
        
    }
    for(let i=0;i<record.length;i++){
        let [state, id, nick]=record[i].split(' ');
        if(state==='Enter'){
            answer.push(obj[id]+'님이 '+'들어왔습니다.')
        }else if(state==='Leave'){
            answer.push(obj[id]+'님이 '+'나갔습니다.')
        }
        
    }
    return answer;
}