Why does the SP.SOD.executeFunc function not work properly?

Question

I use this code to compare two dates, the date of today and the date in the list item. On the screen the dates look fine but when I check them in the debugger the dates are way off. Some are even one year ahead. Why does the code return a different date than what I see on the screen?

<script type="text/javascript">
SP.SOD.executeFunc("clienttemplates.js", "SPClientTemplates", function() { 
    SPClientTemplates.TemplateManager.RegisterTemplateOverrides({
        OnPostRender: function (ctx) {
            // get today's date
            var today = new Date();
            var rows = ctx.ListData.Row;
            for (var i = 0; i < rows.length; i++) {
                // get the date set in your date YourDateField
                var itemDate = new Date(rows[i]['DueDate']);
                var rowId = GenerateIIDForListItem(ctx, rows[i]);
                var row = document.getElementById(rowId);
        console.log("itemdate: " + itemDate);
                if (row!=null&&itemDate <= today) {                  
                    row.style.backgroundColor = '#FF0000';                  
                }
            }
        }
    });
});
</script>

Does anyone have a clue?

Answer 1

This is a known behavior in SharePoint. SharePoint stores all its date/time fields in UTC time.

So, when you try to access the date values using JSOM or REST endpoints that returns the date string in a format that is specific to the regional settings of the person asking for them.

The causes and solutions for this issue are explained in detail in below article:

SharePoint time, is not your time, is not their time

Additional references:

1. SharePoint JSOM datetime values in different timezones