record_collection.js

// Setup
var collection = {
    "2548": {
      "album": "Slippery When Wet",
      "artist": "Bon Jovi",
      "tracks": [ 
        "Let It Rock", 
        "You Give Love a Bad Name" 
      ]
    },
    "2468": {
      "album": "1999",
      "artist": "Prince",
      "tracks": [ 
        "1999", 
        "Little Red Corvette" 
      ]
    },
    "1245": {
      "artist": "Robert Palmer",
      "tracks": [ ]
    },
    "5439": {
      "album": "ABBA Gold"
    }
};
// Keep a copy of the collection for tests
var collectionCopy = JSON.parse(JSON.stringify(collection));

// Only change code below this line
function updateRecords(id, prop, value) {
  if (prop !== "" && value !== "") {
    if(collection[id][prop]) {
        collection[id][prop].push(value);
    }
    else {
        collection[id][prop]=[value];
    }
  } 
  else if (value !== "") {
    collection[id][prop] = value;
  } 
  else {
    delete collection[id][prop];
  }

return collection;
}

// Alter values below to test your code
console.log(updateRecords(1245, "album", "I want to rock again"));