Format JavaScript date as yyyy-mm-dd

Question

I have a date with the format Sun May 11,2014. How can I convert it to 2014-05-11 using JavaScript?

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Answer 1

toISOString() assumes your date is local time and converts it to UTC. You will get an incorrect date string.

The following method should return what you need.

Date.prototype.yyyymmdd = function() {         

    var yyyy = this.getFullYear().toString();                                    
    var mm = (this.getMonth()+1).toString(); // getMonth() is zero-based         
    var dd  = this.getDate().toString();             

    return yyyy + '-' + (mm[1]?mm:"0"+mm[0]) + '-' + (dd[1]?dd:"0"+dd[0]);
};

Source: https://blog.justin.kelly.org.au/simple-javascript-function-to-format-the-date-as-yyyy-mm-dd/

Answer 2

No library is needed

Just pure JavaScript.

The example below gets the last two months from today:

var d = new Date()
d.setMonth(d.getMonth() - 2);
var dateString = new Date(d);
console.log('Before Format', dateString, 'After format', dateString.toISOString().slice(0,10))

Answer 3

Just leverage the built-in toISOString method that brings your date to the ISO 8601 format:

yourDate.toISOString().split('T')[0]

Where yourDate is your date object.

Edit: @exbuddha wrote this to handle time zone in the comments:

const offset = yourDate.getTimezoneOffset()
yourDate = new Date(yourDate.getTime() - (offset*60*1000))
return yourDate.toISOString().split('T')[0]

Answer 4

Retrieve year, month, and day, and then put them together. Straight, simple, and accurate.

function formatDate(date) {
    var year = date.getFullYear().toString();
    var month = (date.getMonth() + 101).toString().substring(1);
    var day = (date.getDate() + 100).toString().substring(1);
    return year + "-" + month + "-" + day;
}

//Usage example:
alert(formatDate(new Date()));

Answer 5

When ES2018 rolls around (works in chrome) you can simply regex it

(new Date())
    .toISOString()
    .replace(
        /^(?<year>\d+)-(?<month>\d+)-(?<day>\d+)T.*$/,
        '$<year>-$<month>-$<day>'
    )

2020-07-14

Or if you'd like something pretty versatile with no libraries whatsoever

(new Date())
    .toISOString()
    .match(
        /^(?<yyyy>\d\d(?<yy>\d\d))-(?<mm>0?(?<m>\d+))-(?<dd>0?(?<d>\d+))T(?<HH>0?(?<H>\d+)):(?<MM>0?(?<M>\d+)):(?<SSS>(?<SS>0?(?<S>\d+))\.\d+)(?<timezone>[A-Z][\dA-Z.-:]*)$/
    )
    .groups

Which results in extracting the following

{
    H: "8"
    HH: "08"
    M: "45"
    MM: "45"
    S: "42"
    SS: "42"
    SSS: "42.855"
    d: "14"
    dd: "14"
    m: "7"
    mm: "07"
    timezone: "Z"
    yy: "20"
    yyyy: "2020"
}

Which you can use like so with replace(..., '$<d>/$<m>/\'$<yy> @ $<H>:$<MM>') as at the top instead of .match(...).groups to get

14/7/'20 @ 8:45

Answer 6

Here is one way to do it:

var date = Date.parse('Sun May 11,2014');

function format(date) {
  date = new Date(date);

  var day = ('0' + date.getDate()).slice(-2);
  var month = ('0' + (date.getMonth() + 1)).slice(-2);
  var year = date.getFullYear();

  return year + '-' + month + '-' + day;
}

console.log(format(date));