What is wrong with my for...in loop? / How to reference object names? (codecademy, javascript)

Question

var friends = {
    bill: {
        firstName: "Bill",
        lastName: "Gates",
        number: "(206) 555-5555",
        address: ['One Microsoft Way','Redmond','WA','98052'],
    },

    steve: {
        firstName: "Steve",
        lastName: "Jobs",
        number: "(408) 555-5555",
        address: ['1 Infinite Loop','Cupertino','CA','95014']
    }
};



var list = function(friends) {
    for (var i in friends) {
        console.log(friends[i]);
    }
};

I'm asked to log the names of the two objects to the console, but I'm confused about how to do this. Codecademy doesn't make it clear enough for me to understand. Can you? Desired output:

bill
steve

note: i do NOT want friends[i].firstname, I want the names of the objects friends[i].

Answer 1

It should be:

for (var i in friends) {
    console.log(i);
}

This is because for...in loops through the keys of the object.

Also, I suggest a different variable name, such as friend instead of i, because i usually means a number or index.

Answer 2

In this case i itself is the property name

for (var i in friends) {
  console.log(i);
}

Answer 3

You have to invoke the function list, like this

list(friends);

And in the list, you just have to print the name like this

var list = function(friends) {
    for (var name in friends) {
        console.log(name);
    }
};

In the ES5 supported implementations, you can simply use

Object.keys(friends);

If you use underscore.js, you can use _.keys, like this

_.keys(friends);