Date and Time Fundamentals

Managing dates and times properly is one of the most difficult things to get right in software. This is mostly due to us stupid humans and the how we have introduced nuance into our calendars and clocks. In this session, I will help you straighten it all out. We will cover general concepts such as UTC and GMT, daylight savings time, local time vs. instantaneous time, time zones and the different time zone databases, ISO8601 standards, important date-time gotchas, and more. We will dive deep into classes for managing time in the Microsoft .Net framework, including DateTime, DateTimeOffset and TimeZoneInfo. We will then take a look at NodaTime - a C# library aimed at replacing those classes. We will also look at the JavaScript Date object, and several JavaScript libraries including MomentJS, TimezoneJS, and jsTimeZoneDetect. Code samples will be in either C# or JavaScript, but much of the information is relevant to any modern software language or architecture.