From Roman Emperors to Temporal API: Conquering Date and Time in JS

Date and time handling is a common cause of bugs in JS code. The main reasons are the complexity of the time phenomenon itself and poorly designed APIs.

In the first part of the talk, we will analyze the main problematic topics: calendar dates, time scales, time zones, and regional formatting features. I will tell the story of how the reforms of the Roman emperors, British railways, and a poorly designed Date API affect the quality of our code.

In the second part of the talk, we'll take a look at Temporal, a new API for working with dates and time that will soon appear in JavaScript. We will analyze its conceptual basis, look at code examples, formulate pros and cons, and think about problems during migration.