text: const users = []
  
  const addUser = ({ id, username, room }) => {
      username = username.trim().toLowerCase()
      room = room.trim().toLowerCase()
  
      if (!username || !room) {
          return {
              error: 'Username and room are required!'
          }
      }
  
      const existingUser = users.find((user) => {
          return user.room === room && user.username === username
      })
  
      if (existingUser) {
          return {
              error: 'Username is in use...'
          }
      }
  
      const user = { id, username, 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) => {
      return users.find((user) => user.id === id)
  }
  
  const getUsersInRoom = (room) => {
      room = room.trim().toLowerCase()
      return users.filter((user) => user.room === room)
  }
  
  module.exports = {
      addUser,
      removeUser,
      getUser,
      getUsersInRoom
  }