Determining the day of the week from a date is essential for scheduling applications, calendar components, and business logic that depends on weekdays. As the creator of CoreUI, a widely used open-source UI library, I’ve built numerous calendar and scheduling components that require precise weekday calculations. From my expertise, the most reliable solution is to use the getDay() method, which returns a number from 0-6 representing the day of the week. This method is consistent across all browsers and provides the foundation for both numeric and text-based weekday representations.