Time Utilities

Date formatting, epoch conversion, and timezone helpers.

Time Utilities

The Time Utilities module (lib/time.ts) provides standardized date and time helper functions used across the application.

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Core Functions

Function	Purpose
formatTimeRange(start, end)	Formats an epoch range into “6:00 AM - 8:00 AM” display string
toLocalEpoch(date)	Converts a Date object to epoch milliseconds in the local timezone
fromEpoch(ms)	Converts epoch milliseconds to a dayjs object
isToday(epoch)	Checks if an epoch timestamp falls on the current calendar day
getRelativeDay(epoch)	Returns “Today”, “Tomorrow”, or the formatted date string

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Timezone Safety

All time operations use dayjs with timezone awareness. Epoch timestamps stored in SQLite and Convex are always in UTC. Display formatting always converts to the device’s local timezone.