//state에 activeChatRoom 추가
state = {
    usersRef: firebase.database().ref("users"),
    users: [],
    activeChatRoom:""
  }

//ChatRoom 얻기
getChatRoomId = (userId) => {
    const currentUserId = this.props.user.uid
    return userId > currentUserId
      ? `${userId}/${currentUserId}`
      : `${currentUserId}/${userId}`
  }

//changeChatRoom 방 바뀌었을때
  changeChatRoom=(user)=>{
    const chatRoomId = this.getChatRoomId(user.uid);
    const chatRoomData = {
      id:chatRoomId,
      name:user.name,
    }
    this.props.dispatch(setCurrentChatRoom(chatRoomData))
    this.props.dispatch(setPrivateChatRoom(true));
    this.activeChatRoom(user.uid);
  }

//활성화된 ChatRoom
  activeChatRoom=(userId) =>{
    this.setState({activeChatRoom:userId})
  }

//활성화 되었을경우 배경색상 교체하기
renderDirectMessages = () => {
    const { users } = this.state;
    return (
      users.length > 0 &&
      users.map(user => (
        <li key={user.uid} 
        style={{
          backgroundColor:user.uid===this.state.activeChatRoom 
            &&"#ffffff45"
          }}
          onClick={() => this.changeChatRoom(user)}>
          # {user.name}
        </li>
      ))
    );
  }