Modify an Array Stored in an Object Number Output

JavaScript
1

Tell us what’s happening:
I don’t know why I get an output of 4, the number of friends (it changes when you add more friends, that’s why I guess it is their count).
I can see my code is a bit different than the solution and I would understand it not working at all, but I don’t understand how I get a number output.

Your code so far


let user = {
name: 'Kenneth',
age: 28,
data: {
  username: 'kennethCodesAllDay',
  joinDate: 'March 26, 2016',
  organization: 'freeCodeCamp',
  friends: [
    'Sam',
    'Kira',
    'Tomo'
  ],
  location: {
    city: 'San Francisco',
    state: 'CA',
    country: 'USA'
  }
}
};

function addFriend(userObj, friend) {
// Only change code below this line
let newArr = userObj.data.friends.push(friend);
return newArr;
// Only change code above this line
}

console.log(addFriend(user, 'Pete'));

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User Agent is: Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/86.0.4240.111 Safari/537.36.

Challenge: Modify an Array Stored in an Object

Link to the challenge:

2

look at the part for return value