Number of days in month

JavaScript, Date · Jun 13, 2021

Gets the number of days in the given month of the specified year.

  • Use the Date constructor to create a date from the given year and month.
  • Set the days parameter to 0 to get the last day of the previous month, as months are zero-indexed.
  • Use Date.prototype.getDate() to return the number of days in the given month.
const daysInMonth = (year, month) => new Date(year, month, 0).getDate();
daysInMonth(2020, 12)); // 31
daysInMonth(2024, 2)); // 29

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