Round a timestamp to the nearest date

Here is a clean way to get just the date in one line with no dependencies:

let d = new Date().setHours(0, 0, 0, 0);

Well, using js you can do:

var d = new Date(1417628530199);
d.setHours(0);
d.setMinutes(0);
d.setSeconds(0);
d.setMilliseconds(0);

A shorter way of writing it is d.setHours(0, 0, 0, 0);

Using Moment.js, you can use the following code to round everything to the beginning of the day:

moment().startOf('day').toString();
// -> Prints out "Fri Dec 05 2014 00:00:00 GMT-0800"

You can read more about startOf() in the docs.

Just construct a new Date from the existing one using only the year, month, and date. Add half a day to ensure that it is the closest date.

var offset = new Date(Date.now() +43200000);
var rounded = new Date(offset .getFullYear(),offset .getMonth(),offset .getDate());
console.log(new Date());
console.log(rounded);

Since this seems to have a small footprint, it can also be useful to extend the prototype to include it in the Date "class".

Date.prototype.round = function(){
    var dateObj = new Date(+this+43200000);
    return new Date(dateObj.getFullYear(), dateObj.getMonth(), dateObj.getDate());
};
console.log(new Date().round());

Minimized:

Date.prototype.round = function(){var d = new Date(+this+43200000);return new Date(d.getFullYear(), d.getMonth(), d.getDate());};