Adding business hours to SLA deadlines in JavaScript with Temporal

A developer describes how a support ticket SLA of four business hours, arriving late on a Friday, becomes tricky once weekends, lunch breaks, and holidays are factored in. Hand-written date code often fails on such cases, including timezone shifts, night shifts, and daylight saving changes. To address this, the author built temporal-workdays, a library that handles business days and hours on top of the JavaScript Temporal API. The library preserves the input type, so time of day and time zone remain intact. It also supports custom weekends, holiday lists, and rule-based holidays such as the fourth Thursday of November.