Core reference

@beemvp/beeui-core holds the platform-free logic the components are built on: calendar-date arithmetic, anchored-overlay positioning, and the overlay-runtime primitives. It has no React dependency and renders nothing.

Most applications never import it directly — the components already do. Reach for it when you are building a surface BeeUI does not provide and you want the same date semantics or positioning maths behind it, which is why most of this surface is classified advanced-consumer rather than consumer.

The Classification column carries exactly two values on this page. advanced-consumer means public and supported, but intended for building a surface BeeUI does not provide — not something a typical application imports. normal-consumer means ordinary application API. cn is the only entry in the second group: it merges class strings. The calendar-date utilities are the same ones Dates and times documents behaviourally.

Values (25)

Name	Signature	Description	Classification	Source
addCalendarDays	(date: CalendarDate, amount: number): CalendarDate	Adds (or subtracts, for a negative amount) whole days, normalizing month/year overflow.	advanced-consumer	packages/core/src/utils/calendar-date.ts
addCalendarMonths	(date: CalendarDate, amount: number): CalendarDate	Adds (or subtracts) whole calendar months.	advanced-consumer	packages/core/src/utils/calendar-date.ts
addCalendarYears	(date: CalendarDate, amount: number): CalendarDate	Adds (or subtracts) whole years, clamping Feb 29 to Feb 28 in a non-leap target year.	advanced-consumer	packages/core/src/utils/calendar-date.ts
clampCalendarDate	(date: CalendarDate, min?: CalendarDate | null, max?: CalendarDate | null): CalendarDate	Clamps a date into an inclusive [min, max] range, returning the nearer bound when the date falls outside it and the date unchanged otherwise.	advanced-consumer	packages/core/src/utils/calendar-date.ts
clockTimeFromLocalDate	(date: Date): ClockTime	The ClockTime counterpart to fromLocalDate: reads local-timezone getHours()/getMinutes() only — the exact reverse of passing a time argument to toLocalDate.	advanced-consumer	packages/core/src/utils/calendar-date.ts
cn	(...inputs: ClassValue[]): string	Merges class-name inputs (strings, arrays, conditional objects) into one deduplicated Tailwind/Uniwind class string, later classes winning on conflict.	normal-consumer	packages/core/src/utils/cn.ts
compareCalendarDates	(a: CalendarDate, b: CalendarDate): number	Field-order comparator: negative when a is earlier, positive when later, 0 when equal.	advanced-consumer	packages/core/src/utils/calendar-date.ts
constrainOverlayViewportToKeyboard	(viewportRect: AnchoredOverlayRect, keyboardRect?: AnchoredOverlayRect | null): AnchoredOverlayRect	Shrinks the usable viewport rect to exclude the area the on-screen keyboard covers, so an anchored overlay repositions above it instead of behind it.	advanced-consumer	packages/core/src/utils/overlay-runtime.ts
createOverlayDismissStack	(): OverlayDismissStack	Creates an empty, mutable dismiss stack an application-root overlay runtime pushes/pops open overlay scopes onto, so global dismissal (Escape/outside-press) always targets the topmost one.	advanced-consumer	packages/core/src/utils/overlay-runtime.ts
fromLocalDate	(date: Date): CalendarDate	The sole sanctioned Date → CalendarDate boundary (ADR-008): reads local-timezone getters only, the exact reverse of toLocalDate.	advanced-consumer	packages/core/src/utils/calendar-date.ts
getCalendarDayOfWeek	(date: CalendarDate): number	0 = Sunday … 6 = Saturday (matches Date.prototype.getUTCDay()/Intl day-index convention).	advanced-consumer	packages/core/src/utils/calendar-date.ts
getCalendarMonthGrid	(options: CalendarMonthGridOptions): CalendarMonthGridDay[][]	Generates the full-week grid for a month: one array per week, each with exactly 7 CalendarMonthGridDay cells (Sunday/Monday-first per weekStartsOn).	advanced-consumer	packages/core/src/utils/calendar-date.ts
getDaysInMonth	(year: number, month: number): number	month must be an integer 1–12.	advanced-consumer	packages/core/src/utils/calendar-date.ts
getSafeAreaCollisionPadding	(hostRect: AnchoredOverlayRect, windowRect: AnchoredOverlayRect, safeAreaInsets: Partial<AnchoredOverlayInsets>): AnchoredOverlayInsets	Combines a host rect, the window rect and the platform safe-area insets into the collision padding the anchored-overlay kernel needs to keep clear of notches, home indicators and status bars.	advanced-consumer	packages/core/src/utils/overlay-runtime.ts
isCalendarDateDisabled	(date: CalendarDate, options: CalendarDateDisabledOptions = {}): boolean	Reports whether a date falls outside the supplied min/max range or matches a disabled-dates predicate.	advanced-consumer	packages/core/src/utils/calendar-date.ts
isCalendarDateWithinRange	(date: CalendarDate, min?: CalendarDate | null, max?: CalendarDate | null): boolean	Reports whether a date falls within an inclusive [min, max] range; a missing bound is treated as unbounded on that side.	advanced-consumer	packages/core/src/utils/calendar-date.ts
isLeapYear	(year: number): boolean	Reports whether the given year is a leap year using the standard Gregorian rule (divisible by 4, not by 100 unless also by 400).	advanced-consumer	packages/core/src/utils/calendar-date.ts
isSameCalendarDate	(a: CalendarDate | null | undefined, b: CalendarDate | null | undefined): boolean	Reports whether two calendar dates (or null/undefined) represent the exact same day; two null/undefined values are not considered the same date.	advanced-consumer	packages/core/src/utils/calendar-date.ts
isValidCalendarDate	(date: CalendarDate): boolean	Reports whether a value is a structurally valid CalendarDate (real year/month/day combination, not just the right shape).	advanced-consumer	packages/core/src/utils/calendar-date.ts
mergeOverlayCollisionPadding	(first: AnchoredOverlayCollisionPadding | undefined, second: AnchoredOverlayCollisionPadding | undefined): AnchoredOverlayInsets	Merges two partial collision-padding objects, the second overriding the first per edge, with an default of 0 for an edge neither one sets.	advanced-consumer	packages/core/src/utils/overlay-runtime.ts
parseISODateString	(iso: string): CalendarDate | null	Parses a "YYYY-MM-DD" string by splitting/regex-matching its fields directly.	advanced-consumer	packages/core/src/utils/calendar-date.ts
resolveAnchoredOverlayPosition	(options: ResolveAnchoredOverlayPositionOptions): AnchoredOverlayPosition	Computes the anchored overlay’s final placement (side, alignment, coordinates) from the anchor rect, viewport, and collision/flip/shift options passed in.	advanced-consumer	packages/core/src/utils/anchored-overlay.ts
toISODateString	(date: CalendarDate): string	Never round-trips through Date/Date.parse — direct field formatting only.	advanced-consumer	packages/core/src/utils/calendar-date.ts
toLocalDate	(date: CalendarDate, time?: ClockTime): Date	The sole sanctioned CalendarDate → Date boundary (ADR-008): constructs via the local-timezone Date constructor, so a date-only value always lands on local midnight (or the given local wall-clock time) of the same…	advanced-consumer	packages/core/src/utils/calendar-date.ts
windowRectToHostRect	(rect: AnchoredOverlayRect, hostRect: AnchoredOverlayRect): AnchoredOverlayRect	Converts a rect expressed in window coordinates into one expressed relative to the given host element’s rect, for overlays rendered inside a scrollable or transformed host.	advanced-consumer	packages/core/src/utils/overlay-runtime.ts

Types (20)

Name	Signature	Description	Source
AnchoredOverlayAlign	'start' | 'center' | 'end'	—	packages/core/src/utils/anchored-overlay.ts
AnchoredOverlayAvailableSpace	AnchoredOverlayInsets	—	packages/core/src/utils/anchored-overlay.ts
AnchoredOverlayCollisionPadding	number | Partial<AnchoredOverlayInsets>	—	packages/core/src/utils/anchored-overlay.ts
AnchoredOverlayDirection	'ltr' | 'rtl'	—	packages/core/src/utils/anchored-overlay.ts
AnchoredOverlayInsets	{ top: number; right: number; bottom: number; left: number; }	—	packages/core/src/utils/anchored-overlay.ts
AnchoredOverlayOverflow	AnchoredOverlayInsets & { total: number; }	—	packages/core/src/utils/anchored-overlay.ts
AnchoredOverlayPlacement	'top' | 'right' | 'bottom' | 'left'	—	packages/core/src/utils/anchored-overlay.ts
AnchoredOverlayPosition	{ x: number; y: number; placement: AnchoredOverlayPlacement; align: AnchoredOverlayAlign; flipped: boolean; shifted: boolean; placementOverflow: AnchoredOverlayOverflow; overflow: AnchoredOverlayOverflow; availableSpace: AnchoredOverlayAva…	—	packages/core/src/utils/anchored-overlay.ts
AnchoredOverlayRect	{ x: number; y: number; width: number; height: number; }	—	packages/core/src/utils/anchored-overlay.ts
AnchoredOverlaySize	{ width: number; height: number; }	—	packages/core/src/utils/anchored-overlay.ts
CalendarDate	{ year: number; month: number; day: number; }	A plain, timezone-free calendar day.	packages/core/src/utils/calendar-date.ts
CalendarDateDisabledOptions	{ isDateDisabled?: (date: CalendarDate) => boolean; max?: CalendarDate | null; min?: CalendarDate | null; }	—	packages/core/src/utils/calendar-date.ts
CalendarMonthGridDay	{ date: CalendarDate; isCurrentMonth: boolean; }	—	packages/core/src/utils/calendar-date.ts
CalendarMonthGridOptions	{ month: number; weekStartsOn?: CalendarWeekStartsOn; year: number; }	—	packages/core/src/utils/calendar-date.ts
CalendarWeekStartsOn	1 | 2 | 3 | 4 | 5 | 6 | 7	ISO 8601 / Intl weekInfo convention: 1 = Monday … 7 = Sunday.	packages/core/src/utils/calendar-date.ts
ClockTime	{ hour: number; minute: number; }	A plain, timezone-free wall-clock time.	packages/core/src/utils/calendar-date.ts
OverlayDismissHandler	(reason: OverlayDismissReason) => void	—	packages/core/src/utils/overlay-runtime.ts
OverlayDismissReason	'back' | 'escape' | 'outside-press' | 'anchor-unmount'	—	packages/core/src/utils/overlay-runtime.ts
OverlayDismissStack	{ register: (id: string, handler: OverlayDismissHandler) => void; unregister: (id: string) => void; isTopmost: (id: string) => boolean; dismissTop: (reason: OverlayDismissReason) => boolean; dismissIfTopmost: (id: string, reason: OverlayDi…	—	packages/core/src/utils/overlay-runtime.ts
ResolveAnchoredOverlayPositionOptions	{ anchorRect: AnchoredOverlayRect; overlaySize: AnchoredOverlaySize; viewportRect: AnchoredOverlayRect; placement?: AnchoredOverlayPlacement; align?: AnchoredOverlayAlign; direction?: AnchoredOverlayDirection; sideOffset?: number; alignOff…	—	packages/core/src/utils/anchored-overlay.ts