refactor: use isLeapYear (TheAlgorithms#1638)

Author: vil02

Conversions/DateDayDifference.js

@@ -6,13 +6,8 @@
  Algorithm & Explanation : https://ncalculators.com/time-date/date-difference-calculator.htm
 */
 
-// Internal method for make calculations easier
-constisLeap=(year)=>{
-if(year%400===0)returntrue
-elseif(year%100===0)returnfalse
-elseif(year%4===0)returntrue
-elsereturnfalse
-}
+import{isLeapYear}from'../Maths/LeapYear'
+
 constDateToDay=(dd,mm,yyyy)=>{
 return(
 365*(yyyy-1)+
@@ -21,7 +16,7 @@ const DateToDay = (dd, mm, yyyy) =>{
 Math.floor((yyyy-1)/400)+
 dd+
 Math.floor((367*mm-362)/12)+
-(mm<=2 ? 0 : isLeap(yyyy) ? -1 : -2)
+(mm<=2 ? 0 : isLeapYear(yyyy) ? -1 : -2)
 )
 }
 

Timing-Functions/GetMonthDays.js

@@ -6,6 +6,8 @@
  e.g.: mahfoudh.arous.com ->false
 */
 
+import{isLeapYear}from'../Maths/LeapYear'
+
 constgetMonthDays=(monthNumber,year)=>{
 constthe31DaysMonths=[1,3,5,7,8,10,12]
 constthe30DaysMonths=[4,6,9,11]
@@ -26,11 +28,8 @@ const getMonthDays = (monthNumber, year) =>{
 return30
 }
 
-// Check for Leap year
-if(year%4===0){
-if(year%100!==0||(year%100===0&&year%400===0)){
-return29
-}
+if(isLeapYear(year)){
+return29
 }
 
 return28

Timing-Functions/test/GetMonthDays.test.js

@@ -1,16 +1,33 @@
 import{getMonthDays}from'../GetMonthDays'
 
 describe('Get the Days of a Month',()=>{
-it('expects to return 28',()=>{
-expect(getMonthDays(2,2018)).toEqual(28)
-})
-
-it('expects to return 30',()=>{
-expect(getMonthDays(6,254)).toEqual(30)
-})
-
-it('expects to return 29',()=>{
-expect(getMonthDays(2,2024)).toEqual(29)
+it.each([
+[1,2024,31],
+[2,2024,29],
+[3,2024,31],
+[4,2024,30],
+[5,2024,31],
+[6,2024,30],
+[7,2024,31],
+[8,2024,31],
+[9,2024,30],
+[10,2024,31],
+[11,2024,30],
+[12,2024,31],
+[1,2023,31],
+[2,2023,28],
+[3,2023,31],
+[4,2023,30],
+[5,2023,31],
+[6,2023,30],
+[7,2023,31],
+[8,2023,31],
+[9,2023,30],
+[10,2023,31],
+[11,2023,30],
+[12,2023,31]
+])('Month %i in year %i has %i days',(month,year,expected)=>{
+expect(getMonthDays(month,year)).toBe(expected)
 })
 
 it('expects to throw a type error',()=>{