GetMonthDays.js

/**
 function that takes month number and its year and returns the number of days within it
 * @param monthNumber.
 * @param year.
 e.g.: mahfoudh.arous@gmail.com -> true
 e.g.: mahfoudh.arous.com ->false
*/

const getMonthDays = (monthNumber, year) => {
 const the31DaysMonths = [1, 3, 5, 7, 8, 10, 12]
 const the30DaysMonths = [4, 6, 9, 11]

 if (
 !the31DaysMonths.includes(monthNumber) &&
 !the30DaysMonths.includes(monthNumber) &&
 monthNumber !== 2
 ) {
 throw new TypeError('Invalid Month Number.')
 }

 if (the31DaysMonths.includes(monthNumber)) {
 return 31
 }

 if (the30DaysMonths.includes(monthNumber)) {
 return 30
 }

 // Check for Leap year
 if (year % 4 === 0) {
 if (year % 100 !== 0 || (year % 100 === 0 && year % 400 === 0)) {
 return 29
 }
 }

 return 28
}

export { getMonthDays }