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Count the difference between two dates
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| /** | |
| * Returns true if year is a leap year | |
| * @param {Number} year | |
| */ | |
| function isLeapYear(year) { | |
| return (((year % 4 == 0) && (year % 100 !== 0)) || (year % 400 == 0)) | |
| } | |
| /** | |
| * Returns number of days till current month from start of the year | |
| * @param {Number} month | |
| * @param {Number} year | |
| */ | |
| function countDaysTillCurrentMonth(month, year) { | |
| let days = 0 | |
| let monthDayCount = [ | |
| 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 | |
| ] | |
| for (let i = 0; i < month - 1; i++) { | |
| days += monthDayCount[i] | |
| } | |
| return days + ((month > 2) && isLeapYear(year) ? 1 : 0) | |
| } | |
| /** | |
| * Returns number of leap years between two years | |
| * @param {Number} from | |
| * @param {Number} to | |
| */ | |
| function numberOfLeapYears(from, to) { | |
| let i = from | |
| let leapCount = 0 | |
| while (i < to) { | |
| if (isLeapYear(i)) { | |
| leapCount++ | |
| i += 4 | |
| } else { | |
| i++ | |
| } | |
| } | |
| return leapCount | |
| } | |
| /** | |
| * Returns difference of days between two years | |
| * @param {Number} from | |
| * @param {Number} to | |
| */ | |
| function daysBetweenYears(from, to) { | |
| if (from === to) | |
| return 0 | |
| return ((to - from) * 365) + numberOfLeapYears(from, to) | |
| } | |
| /** | |
| * Returns the difference between two dates | |
| * @param {String} from - date in following format 'YYYY-MM-DD' | |
| * @param {String} to - date in following format 'YYYY-MM-DD' | |
| */ | |
| function countDateDifference(from, to) { | |
| let startDate = { | |
| year: parseInt(from.split('-')[0]), | |
| month: parseInt(from.split('-')[1]), | |
| day: parseInt(from.split('-')[2]) | |
| } | |
| let endDate = { | |
| year: parseInt(to.split('-')[0]), | |
| month: parseInt(to.split('-')[1]), | |
| day: parseInt(to.split('-')[2]) | |
| } | |
| let numberOfDaysTillStartDate = countDaysTillCurrentMonth(startDate.month, startDate.year) + startDate.day | |
| let numberOfDaysTillEndDate = countDaysTillCurrentMonth(endDate.month, endDate.year) + endDate.day + daysBetweenYears(startDate.year, endDate.year) | |
| return Math.abs(numberOfDaysTillEndDate - numberOfDaysTillStartDate - 1) | |
| } | |
| // Test Cases | |
| console.log('Test countDateDifference - start') | |
| console.log(countDateDifference('2020-09-25', '2020-09-28') === 2) // true | |
| console.log(countDateDifference('2020-09-25', '2020-09-29') === 3) // true | |
| console.log(countDateDifference('2000-01-01', '2000-12-31') === 364) // true | |
| console.log(countDateDifference('2000-12-30', '2001-01-02') === 2) // true | |
| console.log(countDateDifference('1999`-12-30', '2001-01-02') === 368) // true | |
| console.log('Test countDateDifference - End') |
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