Week of the year formatting issue

I noticed that jquery's datepicker and globalize don't compute the same way the week of the year.

While the 01/01/2016 corresponds to the 53 week of 2015 on the datepicker

globalize says that it's the 00 week of 2016 !

As for 01/01/2019, both consider that it's the week 01 of 2019

Here is the fiddle that proves this : http://jsfiddle.net/mbt29szL/

That's quite confusing for users who use the datepicker to create calendar entries, and find out that the week computed by globalize is different from what they'd been expecting !

thanks for your feedback !