Need Help on Javascript record collection

JavaScript
1

You start with an updateRecords function that takes an object like collection , an id , a prop (like artist or tracks ), and a value . Complete the function using the rules below to modify the object passed to the function.

  • Your function must always return the entire object.
  • If prop isn’t tracks and value isn’t an empty string, update or set that album’s prop to value .
  • If prop is tracks but the album doesn’t have a tracks property, create an empty array and add value to it.
  • If prop is tracks and value isn’t an empty string, add value to the end of the album’s existing tracks array.
  • If value is an empty string, delete the given prop property from the album.

Note: A copy of the collection object is used for the tests.

Your code so far


// Setup
var collection = {
2548: {
  albumTitle: 'Slippery When Wet',
  artist: 'Bon Jovi',
  tracks: ['Let It Rock', 'You Give Love a Bad Name']
},
2468: {
  albumTitle: '1999',
  artist: 'Prince',
  tracks: ['1999', 'Little Red Corvette']
},
1245: {
  artist: 'Robert Palmer',
  tracks: []
},
5439: {
  albumTitle: 'ABBA Gold'
}
};

// Only change code below this line
function updateRecords(object, id, prop, value) {
if(prop!="track" && value=="")
{
  var newProp = value;
  return object[3].prop = newProp;
}
else if(prop=="track"&&id.prop==undefined)
{
  var array=[];
  return array = value;
}
else if (prop == "track" && track!="")
{
  return track.push(value);
}
else if(id.track=="")
{
  return delete id.track;
}
return object;
}

updateRecords(collection, 5439, 'artist', 'ABBA');

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 6.3; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/86.0.4240.111 Safari/537.36.

Challenge: Record Collection

Link to the challenge:

2

Do you have a question about your code? You posted the challenge instructions instead of a question.

3

i am trying to solve the task but so far i couldn’t. the code i have written so far is attached to my question

4

what tests are failing? do you have any error in the console?

do you have any idea of what’s going on?

or are you completely confused?

5

not completely confused. my problem is how to connect the arguments with the collection objects, tried different approach but is not working. right now i think the solution is what i need so i can move ahead. i will always revisit javascript object later.

6

Ok this code is very wrong. Most of JS involves using functions and manipulating objects. If you haven’t got these down, you’re likely to have severe issues going forward.

If I take one of the instructions:

If prop isn’t tracks and value isn’t an empty string, update or set that album’s prop to value .

You’ve written:

if (prop!="track" && value=="") {
  var newProp = value;
  return object[3].prop = newProp;
}

So the function has some arguments: object which represents that collection, id is the id of the record (eg “5439”), prop is one of the properties of that record (eg “tracks”), value is a value to give the property.

  • it’s “tracks” not “track”
  • there is no key “3” on the object, and you have the id in the function anyway.
  • there is no prop called “prop”, that’s what you’re assigning to atm.
  • it asks you to return the whole object
  • you access an object like object[key]. So you have an object called object, and you have an id id. So you would access it like object[id]. That gives you the record based on the id.
  • this is also an object, so you access the property on it the same way: object[id][prop]
  • you set values of object properties like object[id][prop] = value
if (prop != "track" && value == "") {
  object[id][prop] = value;
}

So if the function was updateRecords(collection, "5439", "artist", "ABBA"), then

  • object is collection
  • id is "5439"
  • prop is "artist"
  • value is "ABBA".

So object[id][prop] = value evaluates as collection["5439"]["artist"] = "ABBA"

2 Likes
7

Thanks a lot for the explanation. Appreciate

1 Like