Custom format requests not being respected

[mwpowellhtx]

I am trying to specify the custom format specifiers which is not working, such as u, F, m, etc. All I see is this sort of response, 2017-09-13T20:34:10.491Z instead of the expected custom format.

I am calling it something like this:

var dt = new Date();
var s = dt.toString("u"); // or "F", or "m"
var span = $("<span>").append(s);

Taking a step back, I am using the NuGet package, which I think may be another repository.

Personally, I don't care which one is which, both seem to document the same sort of formatting results. However, it just isn't happening.