timestamp getting removed from date javascript

In my javascript file, I have function like below which shows x and y values to me:

 var _tipFunction = function(date,series) {

    var spans = '<table style="border:none">'+series.filter(function(d){
            return d.item!==undefined && d.item!==null
        }).map(function(d){
            return '<tr><td style="color:'+d.options.color+'">'+d.options.label+' </td>'+
                        '<td style="color:#333333;text-align:right">'+yscale.setformat(d.item[d.aes.y])+'</td></tr>'
        }).join('')+'</table>'

    return '<h4>'+xscale.setformat(d3.time.day(date))+'</h4>'
}

this function has 2 args: date and series this date arg is having full date together with timestamp in it, when i tried to print this on console.

But when it comes to last return statement of this function because of d3.time.day(date), only date and day remains. I want to return full date day timestamp.

I tried replacing this with different d3 methods, but it doesn't display anything in that case.

It's not duplicate of what is mentioned in comment, I've tried those answers. Time stops coming on doing that.