JavaScript Objects values updates by IF Statements

Question

I have problem with JavaScript Objects values updates by IF Statements. it is showing error in middle of the code. please suggest. if you need more info please look at the bottom for more info about the project.

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) {
  var collection;
    if (prop != "tracks" && value.length != 0) {
        collection[id][prop] = value;}
    else if(prop === "tracks" && collection[id].hasOwnProperty(tracks) === false){
        collection[id].prop = [];}
    else if(prop === "tracks" && value != ""){
        collection[id][prop].push(value);}
    else if (value ===""){
        delete collection[id][prop];}

    return collection;
};

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:

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.

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

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

Hints:

Use bracket notation when accessing object properties with variables.

Push is an array method you can read about on Mozilla Developer Network.

You may refer back to Manipulating Complex Objects Introducing JavaScript Object Notation (JSON) for a refresher.

So... you want us to do your homework for you? Have you tried debugging your code? Most browsers have a developer mode that allows you to inspect and step through code quite easily. What have you tried? Also, see [ask]. Tell us what you want to do, show your [mcve], and show what results you get, including errors and results. — , Jul 20 '18 at 03:55

Ballsigno · Answer 1 · 2018-07-20T04:06:36.433

How about this one?

// Only change code below this line
function updateRecords(id, prop, value) { 
    //var collection; 【Modified 1】I think it's unnecessary. this time I use Global Variable.
    if (prop != "tracks" && value.length != 0) {
        collection[id][prop] = value;}
        // 【Modified 2】 hasOwnProperty(tracks) → hasOwnProperty("tracks")
        // 【Modified 3】 add the condition 'value != ""', just in case.
    else if(prop === "tracks" && collection[id].hasOwnProperty("tracks") === false && value != ""){
        // 【Modified 4】collection[id].prop → collection[id].tracks or collection[id][prop]
        // 【Modified 5】[] → [value]. You need a value as well as initialize, right?
        collection[id].tracks = [value];}
    else if(prop === "tracks" && value != ""){
        collection[id].tracks.push(value);}
        // 【Modified 6】It's okay to keep it, but if it doesn't have a property, there's no reason to run delete.
    else if (value ==="" && collection[id].hasOwnProperty("tracks")){
        delete collection[id][prop];}
    //return collection;
};

Also, I'm not sure your problem since this question is a bit lack of information.
We need a problem exactly, in this case, something like that:

// call
updateRecords("1245", "tracks", "test");
// Getting Error
// Uncaught ReferenceError: tracks is not defined

JavaScript Objects values updates by IF Statements

1 Answers1