There are probably several libraries that offer this functionality, the question is just what your other requirements are. It is also built into most modern web

There are probably several libraries that offer this functionality, the question is just what your other requirements are. It is also built into most modern web browsers, just check out the MDN for Intl.DateTimeFormat with the dayPeriod option [1]. [1]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/DateTimeFormat/DateTimeFormat#dayperiod https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refe...