Why do we need to use the delete operator in the Record Collection challenge?

I just solved the record collection challenge after many failed attempts. I feel I still need to revisit the solution to really understand what was going on, and especially wrap my head around the delete operator.

To get everything green I had to used the delete operator in the very last ELSE statement to delete any submissions what had empty values.

In every other condition where I have valid data in the function call I will consequently make some change to the collection object. But when have a function call with incomplete data such as an empty track.

 updateRecords(2548, "tracks", "")

I think that I just I need to leave the collection object alone. and exit the function with.

return collection;

and be done with it. I can just skip the object manipulation process entirely. But in order to pass the exercise I needed to to delete the empty property like this.

delete collection[id][prop];

But since I don’t add any property in the function when the value is empty , why would I then need to delete a property that, to my knowledge, I never added in the first place? I assume the property and value only exist in the function call, but never touch the object unless I code it so. It this a matter of how the test itself is designed, or is there a good reason for developers to use delete in this manner in similar if else statements that manipulate an object?

Take this test case:

After updateRecords(2548, "artist", ""), artist should not be set

Before this call, collection number 2548 has an artist property. From an interface point of view, it’s like a cryptic way of telling the program to delete that record’s artist property. So if this was a “real” program, and you wanted to delete a record’s field for some reason, this is how you’d do it.

Hope that made sense.

Hello kevcomedia and thanks for replying to my post.

Your answer is very surprising to me but it does make sense.

I will have to test the function for myself outside of the code editor in freeCodeCamp
and see how a function call with empty value really affects the object.