Javascript date - Leading 0 for days and months where applicable

Question

Is there a clean way of adding a 0 in front of the day or month when the day or month is less than 10:

var myDate = new Date();
var prettyDate =(myDate.getFu         


        

Answer 1

No, there is no nice way to do it. You have to resort to something like:

var myDate = new Date();

var year = myDate.getFullYear();

var month = myDate.getMonth() + 1;
if(month <= 9)
    month = '0'+month;

var day= myDate.getDate();
if(day <= 9)
    day = '0'+day;

var prettyDate = year +'-'+ month +'-'+ day;

Answer 2

The easiest way to do this is to prepend a zero and then use .slice(-2). With this function you always return the last 2 characters of a string.

var month = 8;

var monthWithLeadingZeros = ('0' + month).slice(-2);

Checkout this example: http://codepen.io/Shven/pen/vLgQMQ?editors=101

Answer 3

Yes, get String.js by Rumata and then use:

'%04d-%02d-%02d'.sprintf(myDate.getFullYear(),
                         myDate.getMonth() + 1,
                         myDate.getDate());

NB: don't forget the + 1 on the month field. The Date object's month field starts from zero, not one!

If you don't want to use an extra library, a trivial inline function will do the job of adding the leading zeroes:

function date2str(d) {
    function fix2(n) {
        return (n < 10) ? '0' + n : n;
    }
    return d.getFullYear() + '-' +
           fix2(d.getMonth() + 1) + '-' +
           fix2(d.getDate());
 }

or even add it to the Date prototype:

Date.prototype.ISO8601date = function() {
    function fix2(n) {
        return (n < 10) ? '0' + n : n;
    }
    return this.getFullYear() + '-' +
           fix2(this.getMonth() + 1) + '-' +
           fix2(this.getDate());
 }

usage (see http://jsfiddle.net/alnitak/M5S5u/):

 var d = new Date();
 var s = d.ISO8601date();