[Liubov]

function addFullName(user) {
const obj = {
  firstName: 'value1 ',
  lastName:  'value2',
   };

user.fullName = user.firstName + user.lastName;
}

Expected:

{
"firstName": "Johnny",
"lastName": "Depp",
"fullName": "Johnny Depp"
}

Received:

{
"firstName": "Johnny",
"lastName": "Depp",
"fullName": "JohnnyDepp"
}