Profile Lookup - Do I have to use hasOwnProperty?

JavaScript
1

Tell us what’s happening:
I have a nested if statement that checks to see if the array’s object has a particular property. I do this by placing the the object’s array inside the if parentheses hoping it will evaluate to true or false, but it won’t seem to work. Here is my syntax: if (contacts[i][prop]). prop is a parameter from the function.
The solution I saw requires me to use the method hasOwnProperty. Why won’t my reference to that property return false if it doesn’t have the property?

Your code so far

//Setup
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 (contacts[i].firstName === firstName){
    if (contacts[i][prop]){
      return contacts[i].prop;
    } else { return "No such property";}
  }else { return "No such contact";}
}
// Only change code above this line
}

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

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Your Browser User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/60.0.3112.90 Safari/537.36.

Link to the challenge: