"Returns week number of a specific date. According to the ISO-8601 standard, weeks starting on Monday". Furthermore, the link states that "weekStart Number (optional)
The day number (from 0 (Sunday) to 6 (Saturday)) representing what day of week is considered as a starting point. This parameter is optional because by default Monday (1) is considered as a first day of the week".
So if the default of this optional parameter is 1, why do I have to supply the 1 to it?
Also, why does the link state that the second parameter is a number and then the example passes in a date
"//Sunday is passed as week start console.log(kendo.date.weekInYear(new Date(2017, 0, 9), new Date(2017, 0, 8))); "?
Also, this still returns 1 for me: kendo.date.weekInYear(new Date(2017, 11, 31, 10, 10, 10), new Date(2017, 11, 25))