Iterate Through the Keys of an Object with a for...in Statement - return vs. console.log etc

JavaScript
1

Hello!

Below is my solution for this challenge.
But I have some questions.

  1. Instead of return, I used console.log(counter).
    Result has to be “2”, but if I use console.log, it was “2, undefined”.
    Why is it so??
  2. I understand “user” is variable that has to be in the bracket.
    and “online” is specific root that you can use both bracket and dot notation.
    but how about “obj”? I try using bracket and it failed to read. Why is it so?
let users = {
  Alan: {
    age: 27,
    online: false
  },
  Jeff: {
    age: 32,
    online: true
  },
  Sarah: {
    age: 48,
    online: false
  },
  Ryan: {
    age: 19,
    online: true
  }
};

function countOnline(obj) {
  // change code below this line
  let counter =0;
  for (let user in obj){
    if(obj[user].online){
      counter++
    }
  } return counter;
  // change code above this line
}
console.log(countOnline(users));
2

  1. When you replace the return by the console.log, the first value will be the counter printed, the second value ‘undefined’ is printed from the console.log(countOnline(users));. Since the function call doesn’t return anything, the value from countOnline(users) is undefined.

  2. Do you mean [obj][user] instead of obj[user]? That is because obj is the object that contains the data. In obj[user], user is a variable containing a key value of obj you are looking for.

3

Thank you for clear and the fast reply! :slight_smile: