30-seconds-of-code/snippets/getMonthDays.md

title, tags

title	tags
getMonthDays	date,intermediate

Get the number of days in the month according to the specified month.

• Use new Date(year, monthIndex, day), set the parameter day to 0 to get last day of the previous month.
• Use Date.prototype.getDate to get the day of month.

const getMonthDays = (year, month) => {
  const today = new Date();
  
  return new Date(year || today.getFullYear(), month || (today.getMonth() + 1), 0).getDate();
};

getMonthDays(); // 30
getMonthDays(2020, 2); // 29
getMonthDays(2021, 2); // 28