[프로그래머스] 오픈채팅방

링크: https://programmers.co.kr/learn/courses/30/lessons/42888

function solution(record) {
    const action = [];
    const userInfo = {};
    const states = {
        "Enter": "님이 들어왔습니다.",
        "Leave": "님이 나갔습니다.",
    };
    
    record.forEach((item) => {
        const [state, uid, name] = item.split(" ");
        
        if (state !== "Change") {
            action.push([state, uid]);
        }
        
        if (name) {
            userInfo[uid] = name;
        }
    })
    
    return action.map((item) => `${userInfo[item[1]]}${states[item[0]]}`);
}