record-collection-exercise.js

// You are given a JSON object representing a part of your musical album collection. Each album has several properties and a unique 
// id number as its key. Not all albums have complete information. Write a function which takes an album's id (like 2548), a property prop 
// (like "artist" or "tracks"), and a value (like "Addicted to Love") to modify the data in this collection. If prop isn't "tracks" and 
// value isn't empty (""), update or set the value for that record album's property. Your function must always return the entire collection 
// object. There are several rules for handling incomplete data:

// 1. If prop is "tracks" but the album doesn't have a "tracks" property, create an empty array before adding the new value to the 
// album's corresponding property.

// 2. If prop is "tracks" and value isn't empty (""), push the value onto the end of the album's existing tracks array.

// 3. If value is empty (""), delete the given prop property from the album.

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"
  }
};

function updateRecords(id, prop, value) {
  if(value === "") delete collection[id][prop];
  else if(prop === "tracks") {
    collection[id][prop] = collection[id][prop] || [];
    collection[id][prop].push(value);
  } else {
    collection[id][prop] = value;
  }
  return collection;
}

updateRecords(5439, "artist", "ABBA");