Profile Lookup – open my eyes, please

Profile Lookup – open my eyes, please
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#1

Tell us what’s happening:
Why it doesn’t work?

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.lenth; i++) {
    if (contacts[i].firstName === firstName) {
      if(contacts[i].hasOwnProperty(prop)) {
        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 (Windows NT 6.3; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/65.0.3325.181 Safari/537.36.

Link to the challenge:

UPD: I found a mistake. I wrote “lenth” instead length :confused:
Sry for my stupidity.


#2

Your for loop doesn’t run, because length is misspelled.

Unfortunately, a typo on an object property doesn’t throw an error; instead, contacts.lenth evaluates to undefined, which means the first iteration of the for loop checks 0 < undefined.

undefined coerces to 0, so 0 < undefined returns false, so the loop never runs.


#3

If undefined coerces to 0 in the expression 0 < undefined which returns false, then 0 <= undefined should return true, but it does not. There must be another reason that both expressions actually evaluate to false?


#4

Yep, you’re right, seems I was mistaken. Looks like it actually coerces to NaN (+undefined => NaN), which will evaluate as unequal to any number (but also neither greater than nor less than).