I am a junior backEnd developer.
My colleague do code review for my project.
I write a function as below without typeof.
He recommended use typeof for me when I do Comparison in this case.
I wanna know is typeof necessary in this case and why ??
I am happy my colleague give me some advices.
But I need key reason to push me change my coding style, Thank you.

let users = {
  Leo:{
    age:20,
    style:"Fire"
  },
  Kai:{
    age:30,
    style:"Ice"
  }
}

//My version
function getUser(name){
  let user = users[name];
  if(user === undefined){
    return false
  }
  // do something...
  return true
}

//Colleague version
function getUser(name){
  let user = false;
  if(typeof users[name] === 'undefined'){
    return false
  }
  user = users[name];
  // do something...
  return true
}