@fullcalendar/core 7.1.5

on Node.js Yarn

React

• FIX: <Activity> (React 19.2+, which Next.js uses to keep recent pages alive) (#8112):
  • A hidden calendar restarted its timers when re-rendered. Once removed, those timers kept running and kept the whole calendar in memory
  • TimeGrid and DayGrid views shown again jumped back to scrollTime or today's row, losing the user's scroll position
• FIX: A function event source (events: (info) => …) under a suspended <Suspense> boundary warned "Can't perform a React state update on a component that hasn't mounted yet" when its fetch resolved, and left a timer running (#8092)
• FIX: Strict Mode, in development: the now indicator and today's highlight stopped updating after Strict Mode's simulated remount

Event Rendering

• FIX: DayGrid with dayMaxEvents or dayMaxEventRows:
  • Events hidden behind "+N more" in the last week could hang invisibly past the bottom of the grid, so the month scrolled into empty space (#7581)
  • When true, a day could hide an event behind "+N more" even when the event and the link both fit, such as showing "+2 more" alone where the first event had room
  • When true, an event that didn't fit at first could only come back cut into pieces around other events, or not at all with eventSlicing: false. It can now come back whole, so some days show events they used to hide. Rarely, a day shows a later event where it used to show part of an earlier one

Headers and Titles

• FIX: DayGrid (month, multi-month): day headers that name only the weekday gave dayHeaderContent and the other day header hooks a January 1970 date at midnight UTC, which read as the day before west of UTC. date is now a day in view, at midnight in the calendar's time zone. Code that read it in UTC (such as getUTCDay()) should use dow instead (#7468, #5854)
• FIX: TimeGrid: slot headers in the time axis were only as tall as their labels, so a background, border or hover style from slotHeaderClass covered just the top of the slot
• FIX: List view: listDayFormat: false and listDayAltFormat: false rendered their day headings in the default format instead of turning them off
• FEATURE: view.titleParts: the title's Intl range parts (type, value, and source of startRange, endRange or shared), so a custom toolbar can style parts of the title, such as a lighter year, in every locale and for ranges. Typed as DateTimeRangeFormatPartWithWeek
• FEATURE: slotHeaderContent and the other slot header hooks get textParts and the weekdayText, dayNumberText and monthText getters that day cells have (empty strings in the time grid's axis). dayHeaderContent and listDayHeaderContent get monthText too
• TimeGrid: slot headers between labels have data-time too, like the labeled ones

Event Settings

• FIX: Dragging an event previewed it differently from how it's handled once dropped:
  • To another resource: its source's constraint, overlap and allow were ignored, so it could be dropped where they forbid, and the preview lost its source's colors and classes
  • An all-day event into TimeGrid's timed area: the preview lost its source's colors and classes
  • Back into the calendar it came from: its source's settings, such as allow, were ignored until dropped
  • In from outside with a resourceId, in views without resources: it didn't take its resource's colors and classes until dropped
• FIX: Views without resources, such as timeGridWeek with resources loaded: an event added with calendar.addEvent() and no event source didn't get its resource's eventColor, eventClass or other event settings

Resource Views

• FIX: event.getResources() returned null for each resource that doesn't exist or hasn't been fetched yet. It now leaves them out (#7300)
• FIX: Resource Timeline: a resourceColumnsWidth other than a number, px or %, such as '9.5rem', threw an error, so the view didn't render. It now warns and uses the default, 30%. A resource column's width in another unit warns too, and the column still grows to fill the space
• FIX: Resource Timeline with virtualization: scrolling to a resource added with calendar.addResource(resource, true) could stop a few rows short of it. A regression in v7.1.4
• FIX: resource.toPlainObject() left out the resource's eventColor

Accessibility

• FIX: Prev, next, today and custom toolbar buttons had aria-pressed="false", so screen readers announced them as toggle buttons. Only view buttons have it now (#8042)
• FIX: A view button alone in its toolbar group had role="tab" with no tablist around it. It's now a toggle button with aria-pressed, like grouped view buttons

Misc

• FIX: Skeleton CSS: some structural rules, including the z-index ones that set the stacking order, weren't !important, so without cascade layers an app's CSS could override them (though not in a Tailwind app). All are now, so the stacking order is the same in every setup, and a z-* class on an element from a hook, such as tableHeaderClass, has no effect
• FIX: An event at a wall-clock time skipped by a daylight-saving change (given without an offset) resolves to the time after the change, but startStr/endStr named the skipped time, an hour before start/end. Fed back into addEvent, the string moved the event
• FIX: TypeScript: calendar.off() required a handler, though calling it without one removes all of that name's handlers added with calendar.on()
• INTERNAL: every calendar option has a description and a link to its docs page in the source code, for AI agents and other tools that read it
• INTERNAL: a new, faster test suite on Vitest, replacing Karma