Profile Lookup Basic Question

Tell us what’s happening:
Hi everybody! Just got a very quick and basic question:

Inside my function at the bottom, why does it have to be
return contacts[i][prop]
and why does this not work?
return contacts[i].prop

Any help greatly appreciated!!

Your code so far

var contacts = [
        "firstName": "Akira",
        "lastName": "Laine",
        "number": "0543236543",
        "likes": ["Pizza", "Coding", "Brownie Points"]
        "firstName": "Harry",
        "lastName": "Potter",
        "number": "0994372684",
        "likes": ["Hogwarts", "Magic", "Hagrid"]
        "firstName": "Sherlock",
        "lastName": "Holmes",
        "number": "0487345643",
        "likes": ["Intriguing Cases", "Violin"]
        "firstName": "Kristian",
        "lastName": "Vos",
        "number": "unknown",
        "likes": ["Javascript", "Gaming", "Foxes"]

function lookUpProfile(firstName, prop){
// Only change code below this line
  for(var i = 0; i < contacts.length; i++){
    if(firstName === contacts[i].firstName){
        return contacts[i][prop];
      } else {
        return "No such property";
  return "No such contact";
// Only change code above this line

// Change these values to test your function
lookUpProfile("Akira", "likes");

Your browser information:

Your Browser User Agent is: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:59.0) Gecko/20100101 Firefox/59.0.

Link to the challenge:

1 Like

Thats because prop is a variable and not a property name. This dot operator works only with exact property name.
If you want to inject dynamic property name ( through use of variables) then you must use the brackets without the quotes. If it is enclosed in quotes the JS engine will assume its a actual property name and processes it as such.

Very good to know, thanks a lot for the quick answer!