30-seconds-of-code/javascript/snippets/last-date-of-month.md

title, type, tags, cover, dateModified

title	type	tags	cover	dateModified
Last date of month	snippet	date	polar-bear	2020-10-09T22:01:42+03:00

Returns the string representation of the last date in the given date's month.

• Use Date.prototype.getFullYear(), Date.prototype.getMonth() to get the current year and month from the given date.
• Use the Date constructor to create a new date with the given year and month incremented by 1, and the day set to 0 (last day of previous month).
• Omit the argument, date, to use the current date by default.

const lastDateOfMonth = (date = new Date()) => {
  let d = new Date(date.getFullYear(), date.getMonth() + 1, 0);
  return d.toISOString().split('T')[0];
};

lastDateOfMonth(new Date('2015-08-11')); // '2015-08-30'