Hi Bruse,

Thanks so much for your comprehensive explanation.

The IEnumerable<> (or ICollection<>) in my case is actually a property within a class, (it did not show because I tried to focus on handling that collection property) and I instantiate the property with HashSet(), which should be OK.

However, there is a problem with the code you provided:

        var Cats = [];
        var temp;
        for (var i = 0; i < Categories.length; i++) {
            //temp = { Id: i, Category: Categories[i] };
            temp = { Id: i };
            temp["Category"] = Categories[i];
            Cats = Cats.push(temp);
        }

In the above, "Cats = Cats.push(temp);" does not work. (the "push" does not even show up in intellesence).

In my code I include only jquery-3.3.1.js. Do I miss anything?

Golden