DAYSJS - A TYPESCRIPT / JAVASCRIPT DATE HANDLING LIBRARY

DaysJS is a library that provides base functions for DATE handling. The dates are represented as an integer; the count of days from the Unix epoch (1st January 1970). There is no time component, and as such no need for any time zone manipulation. These functions are meant to be used to support Date libraries you develop. The functions are fast and robust.

This is a port, with permission, of the C++ code by Howard Hinnant which can be found here: https://howardhinnant.github.io/date_algorithms.html.
Howard has also graciously allowed me to include his explanations of the algorithms in the documentation, which is a good thing, cause any attempt I make to explain them would inevitably devolve into a diatribe about the need to include far more primate species in every level of government; and why modern day law enforcement could be entirely replaced by a guild of bounty hunters with cool spaceships.

Also, here is a monkey:

                                            __,__
                                   .--.  .-"     "-.  .--.
                                  / .. \/  .-. .-.  \/ .. \
                                 | |  '|  /   Y   \  |'  | |
                                 | \   \  \ 0 | 0 /  /   / |
                                  \ '- ,\.-"`` ``"-./, -' /
                                   `'-' /_   ^ ^   _\ '-'`
                                       |  \._   _./  |
                                       \   \ `~` /   /
                                        '._ '-=-' _.'
                                           '~---~'