Strange behavior of nulls in JS, how can this be?

Question

JavaScript

It seems that I’m not new to JS, but for some reason I can’t understand this behavior, which is not standard for me personally. It

doesn’t work like that.
And a little from the other side, coming up, working

MB, I’m doing something wrong !?
Or is it the norm?

Answer 1

sorry, but what should work? In the first option, you always set vm.list to null,

function (data) {
    if (Array.isArray(data)) {
         vm.list = vm.list.concat(data);
    } else {
         vm.list = null;
    }
}