Time is a real mess. I never liked how Ruby and JS deal with time, though Rails always get a gold star from me for smooth out a lot of common issues with time and dates. The Ruby on Rails Time API made it pretty easy to calculate and format dates with methods that were sort of the best of Ruby - readable in plain English and easy to remember.
Just wanted to note the wonderful datepickers from our friends at Airbnb. If you include the Moment.js library, the legacy but still required react-addons-shallow-compare, and Airbnb's react-dates, you got yourself one fine looking React Datepicker. This is the first component I have been able to deploy to a project that I really loved so I wanted to share it here.
The react-dates documentation is stellar.
Slim Date Pickins
I am making an expense tracking app based on the excellent tutorial from Andrew Mead. He has a great website, too. This guy really has a knack for explaining concepts well and unlike most tutorials, he doesn't gloss over hard parts with hand-wavy "uh yeah this is weird but just type it" moments. I need to understand everything and his courses scratch that itch.