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Profile LookUp

17 Sep 2016 | FreeCodeCamp

I took a look into this new challenge, and thought it was going to be easy. After few tries, I failed to realize that computer parses, and not necessarily read the same way as I do. I wasn’t accessing right. I miscommunicated with the computer.

The Challenge is:

  • Check if firstName is an actual contact’s firstName and the given property (prop) is a property of that contact
  • If both are true, then return the “value” of that property
  • If firstName does not correspond to any contacts then return "No such contact"
  • If prop does not correspond to any valid properties then return "No such property"
//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

// Only change code above this line
}
// Change these values to test your function
lookUpProfile("Akira", "likes");

The challenge sounds simple, but ah-ha, how do you loop through the nested objects in an array? FreeCodeCamp provided handful of lessons before this challenge. The lesson Iterate through an Array with a For Loop explained:


var arr = [10,9,8,7,6];
for (var i=0; i < arr.length; i++) {
   console.log(arr[i]);
}

//--> 10, 9, 8, 7, 6

All I had to do to loop through an array is putting down array’s name dot length. Sounds easy, but wait! There are many objects and many firstName in the array, how am I going to find the specific property firstName that I am looking for? Another lesson in FreeCodeCamp Accessing Nest Array gave an example using array bracket notation and index.


var myPlants = [
  {
    type: "flowers",
    list: [
      "rose",
      "tulip",
      "dandelion"
    ]
  },
  {
    type: "trees",
    list: [
      "fir",
      "pine",
      "birch"
    ]
  }  
];

var secondTree = myPlants[1].list[1];

//--> secondTree = pine

However this challenge has nested objects in an array, and these are where firstName are located in. FCC’s Accessing Nested Objects lesson teaches that nested object can be accessed by either using dot or bracket notation.


var myStorage = {
  "car": {
    "inside": {
      "glove box": "maps",
      "passenger seat": "crumbs"
     },
    "outside": {
      "trunk": "jack"
    }
  }
};

var gloveBoxContents = myStorage.car.inside["glove box"] ;

//-->gloveBoxContents = maps

Let’s get to work!

We need to access into an array contacts and loop through nested objects until one of arguments matches with the firstName.


function lookUpProfile(firstname, prop) {
    for (var i = 0; i < contacts.length; i++) {
        if (contacts[i].firstName === firstName) {
        }
    }
}

i loops through each nested objects in an array contacts, and until firstName matches. In the challenge, there are rules like if firstName doesn’t match, and if there isn’t any prop, would need to return why cannot complete. If firstName matches and has a prop, then return the value.

function lookUpProfile(firstName, prop){
    for (var i = 0; i < contacts.length; i++) {
        if (contacts[i].firstName === firstName) {
            if (prop in contacts[i]) {
                return contacts[i][prop];
            } else {
                return "No such property";
            }
        }
    }
    return "No such contact";
}

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