ts-days-between-two-dates

Problem Statement

Calculate weekdays and business days between two dates.

Task One: Weekdays Between Two Dates

Calculates the number of weekdays in between two dates.

• Weekdays are Monday, Tuesday, Wednesday, Thursday, Friday.
• The returned count should not include either firstDate or secondDate - e.g. between Monday 07-Oct-2013 and Wednesday 09-Oct-2013 is one weekday.
• If secondDate is equal to or before firstDate, return 0. Expected Results The following scenarios will allow you to validate your application is working as expected: |Start Date | End Date | Result |7th October 2013 | 9th October 2013 | 1 |5th October 2013 | 14th October 2013 | 5 |7th October 2013 | 1st January 2014 | 61 |7th October 2013 | 5th October 2013 | 0

Task Two: Business Days Between Two Dates

Calculate the number of business days in between two dates.

• Business days are Monday, Tuesday, Wednesday, Thursday, Friday, but excluding any dates which appear in the supplied list of public holidays.
• The returned count should not include either firstDate or secondDate - e.g. between Monday 07-Oct-2013 and Wednesday 09-Oct-2013 is one weekday.
• If secondDate is equal to or before firstDate, return 0. Expected Results Sample list of Public Holidays:
• 25th December 2013
• 26th December 2013
• 1st January 2014 Given those public holidays, the following scenarios will allow you to validate your application is working as expected: | Start Date | End Date | Result | 7th October 2013 | 9th October 2013 | 1 | 24th December 2013 | 27th December 2013 | 0 | 7th October 2013 | 1st January 2014 | 59

Task Three: More Holidays

Design a data structure or hierarchy of structures which can define public holidays in a more complex fashion than simple dates. This should cater for things such as:

• Public holidays which are always on the same day, e.g. Anzac Day on April 25th every year.
• Public holidays which are always on the same day, except when that falls on a weekend. e.g. New Year's Day on January 1st every year, unless that is a Saturday or Sunday, in which case the holiday is the next Monday.
• Public holidays on a certain occurrence of a certain day in a month. e.g. Queen's Birthday on the second Monday in June every year. Given this data structure, the BusinessDaysBetweenTwoDates() function should be able to be extended to take a list of public holiday rules, rather than a list of DateTimes, and calculate the number of business days between two dates using those rules to define public holidays.

Solution

Class Structure

HolidayType

• FixedHolidayType
• AdjustedHolidayType
• CertainDayHolidayType

PublicHolidays -> Data structure to manage all HolidayType days

Notes

• The code separates each type of holiday into its own class, this gives a single responsibility to each class. New holiday types can be easily added.
• The abstract base class HolidayType forces each derived class to implement the "isHoliday" function and enables different implementations.
• There is a separation of concerns into different classes to promote readability, testability, reusability and makes it easy to maintain and evolve.
• The PublicHolidays data structure behaves like a list which stores different types of holidays. Each holiday has a different type and specification (resources/holiday-data.json contains sample data).
• The following have been added to make sure the code is "production-ready":
  • Unit test cases
  • Linting using ESLint
  • Code Formatting using Prettier
• The BusinessDayCounter class has been built to be used as an NPM package.
  • npm install days-between-two-dates-utility
  • Import and instantiate BusinessDayCounter
  • Call functions with inputs
    • weekdaysBetweenTwoDates(firstDate: Date, secondDate: Date)
    • businessDaysBetweenTwoDates(firstDate: Date, secondDate: Date, publicHolidays: Date[])
    • businessDaysBetweenTwoDatesUsingDS(firstDate: Date, secondDate: Date) (requires resources/holiday-data.json for holiday types input)