text: const users = [];
  
  const addUser = ({ id, name, roomName }) => {
    let room =roomName
    name = name.trim().toLowerCase();
    room = room.trim().toLowerCase();
  
    const existingUser = users.find((user) => user.room === room && user.name === name);
  
    if(!name || !room) return { error: 'Username and room are required.' };
    if(existingUser) return { error: 'Username is taken.' };
  
    const user = { id, name, room };
  
    users.push(user);
  
    return { user };
  }
  
  const removeUser = (id) => {
    const index = users.findIndex((user) => user.id === id);
  
    if(index !== -1) return users.splice(index, 1)[0];
  }
  
  const getUser = (id) => users.find((user) => user.id === id);
  
  const getUsersInRoom = (room) => users.filter((user) => user.room === room);
  
  module.exports = { addUser, removeUser, getUser, getUsersInRoom };