Basic JavaScript: Record Collection cannot understand

JavaScript
1

Hi, I’ve been stuck in this code challenge for several days. I have read all the posts about it and I didn’t get anything. The explanation given in the challenge is not very enlightening. This is my code right now and with this I don’t get any green check.

function updateRecords(id, prop, value) {
  if (prop === 'tracks' && collection[id]['tracks'] === undefined) {
    collection.id['tracks'] = []; 
  } else if (prop != 'tracks' && value != '') {
    collection.id[prop].push(value);
  } else if (value === '') {
    delete id.prop;
  }
  
  return collection;
}

Thanks a lot.

2

You need to check for the value being passed. An empty value means you are expected to delete a property. Add a value checker to your first if-condition:
if (value && prop === 'tracks' && collection[id]['tracks'] === undefined)

When you want to use a variable reference an object property, you MUST use the bracket notation. Change all the occurences of collection.id[prop] to collection[id][prop]. Also, since only the property tracks is an array, just set the properties with the = operator. Don’t use the Array method .push.

} else if (prop != 'tracks' && value != '') {
   collection[id][prop] = value; 
}

Fix your delete statement.

else if (value === '') {
    delete collection[id][prop];
}

If value is not “”, then your must add the song to the album, even when it has no album:

if (value && prop === 'tracks' && collection[id]['tracks'] === undefined) {
    collection[id]['tracks'] = [];
    collection[id][prop].push(value);
}

Now you are almost in business :slight_smile:
What to do when it does have an album and value is not empty? This condition is missing.

3

Hi thanks for your answer! I changed my code based on what you told me and now I get some green checks but I still don’t get the logic. This is my code now:

function updateRecords(id, prop, value) {
  if (value && prop === 'tracks' && collection[id]['tracks'] === undefined) {
    collection[id]['tracks'] = [];
    collection[id][prop].push(value);
  } else if (prop != 'tracks' && value != '') {
   collection[id][prop] = value; 
  } else if (value === '') {
    delete collection[id][prop];
  }
  return collection;
}

In the first IF statement, how can value and prop be both ‘tracks’?

And in the second one why you do collection[id][prop] = value?

5

Oh ok I get that part now, I was a little confused…
With the code of my last post I only get this error:

After updateRecords(1245, "tracks", "Addicted to Love"), tracks should have "Addicted to Love" as the last element.

But that is done with the first IF isn’t it?

6

No. Because in this case, tracks is not an empty array. The last condition in your if-statement makes the whole block false.
collection[id]['tracks'] === undefined
Therefore, it does not run the first statement for that case.

7

I finally got it done!! I don’t know why but this if else exercise has been the most difficult for me to understand.
Thanks a lot!