Adding days to dates is fundamental for calculating deadlines, scheduling events, and building calendar functionality in web applications. As the creator of CoreUI with over 25 years of development experience, I’ve implemented date calculations in countless scheduling components and business logic scenarios. The most reliable approach is using the setDate() method which automatically handles month boundaries, year transitions, and leap years. This native JavaScript method eliminates edge case bugs that plague manual date arithmetic.

Getting yesterday’s date is essential for data comparisons, log analysis, and building time-sensitive application features. As the creator of CoreUI with over 25 years of development experience, I’ve implemented date calculations in analytics dashboards and reporting components countless times. The most reliable method is using setDate() with getDate() - 1 which automatically handles month and year boundaries. This approach eliminates the complexity of manual date arithmetic and daylight saving time issues.