Changelog

All notable changes to this project will be documented in this file.

The format is based on Keep a Changelog and this project adheres to Semantic Versioning.

@ulm/core and @ulm/leaflet ship on the same version. The scope on each entry names the package that changed.

Sections are drafted from the commit history with npm run changelog:draft and edited before release. To see what is pending, run npm run changelog:preview.

2.0.0 - 2026-10-01

Migrating from 1.x

Time info uses Temporal. Dates in timeInfo are now Temporal.PlainDate, Temporal.PlainDateTime or Temporal.ZonedDateTime, in place of CalendarDate, CalendarDateTime and ZonedDateTime from @internationalized/date. Not every browser supports Temporal yet, so install temporal-polyfill and import Temporal from it:

// 1.x
import { parseDate } from '@internationalized/date';

manager.setTimeInfo('sea-ice', { type: 'single', precision: 'date', value: parseDate('2026-10-01') });

// 2.0
import { Temporal } from 'temporal-polyfill';

manager.setTimeInfo('sea-ice', { type: 'single', precision: 'date', value: Temporal.PlainDate.from('2026-10-01') });

setVisibility is removed. Use setEnabled(layerId, enabled). In 1.x the two did the same thing.

If you work with the XState actors directly:

• A switched-off layer's snapshot value is 'disabled', not { disabled: 'hidden' }. Check it with snapshot.matches('disabled') or snapshot.hasTag('enabled').
• LayerMachineActor, LayerGroupMachineActor and LayerActor default their data types to unknown rather than any. Pass your types, for example LayerActor<LayerData, GroupData>.
• LAYER.UPDATE_VISIBILITY, LAYER.UPDATE_OPACITY, LAYER.UPDATE_TIME_INFO and LAYER.UPDATE_LAYER_DATA are renamed to CHILD.*_CHANGED and are internal. To change a layer, send LAYER.ENABLED, LAYER.DISABLED, LAYER.SET_OPACITY, LAYER.SET_TIME_INFO or LAYER.SET_LAYER_DATA to its actor. To react to changes, listen for the manager's LAYER.*_CHANGED events.

Added

• Add enabled and visible state tags to layer machines
• core: Report layer order changes to adapters and callbacks
• core: Add onLayerDataChanged option to LayerManager
• core: Add inspect option to LayerManager
• core: Move, raise and lower layers within their parent
• core: Reject moving a layer that does not exist
• core: Reject moving a layer into a parent that is not a group
• core: Reject moving a group into itself or a descendant
• core: Reject moving a group into a group unless nesting is allowed
• core: Report moved layers through onLayerMoved
• core: Move a layer from one group into another
• core: Recompute computed opacity when a layer changes group
• core: Report opacity after a move only when it changes
• core: Hide a layer moved into a group that is not showing
• core: Show a switched-on layer moved into a showing group
• core: Carry group visibility through a move
• core: Update a moved group's layers to its new computed opacity
• leaflet: Stack every layer in the manager's order with panes
• leaflet: Fade every kind of layer through its pane
• examples: Reorder layers by drag and drop in the Leaflet example
• core: Tell a newly attached adapter about existing layers
• Breaking: core: Stop exporting internal helpers
• Breaking: core: Use Temporal types for layer time info

Removed

• Breaking: core: Remove internal helpers from the published types

Fixed

• Stop layer actors and emit removals on reset
• Report current computed opacity for nested groups
• Emit LAYER.ADDED visibility from the added layer's state
• core: Start layers and groups in their resolved state from input
• core: Queue parent group updates as actions when adding or removing
• core: Guard add and remove transitions and report rejections
• core: Compute layer opacity from parent messages, not snapshots
• Breaking: core: Own group child order in the layer manager
• Breaking: core: Separate child notifications from manager commands
• leaflet: Make leaflet a peer dependency

Refactor

• Breaking: core: Remove unused validation and opacity helpers
• Breaking: core: Default layer actor types to unknown instead of any
• Breaking: core: Make the disabled state atomic in layer machines
• Breaking: core: Remove setVisibility in favour of setEnabled

1.0.0 - 2026-03-19

Initial release of @ulm/core and @ulm/leaflet, extracted from @ulm/universal-layer-manager.

Added

• core: LayerManager<TLayer, TGroup> class as the primary public API over the XState machine
• core: LayerManagerAdapter<TLayer, TGroup> interface for push-model adapter integration
• core: ManagedLayerInfo — stable, non-XState shape passed to adapter methods and option callbacks
• core: LayerManagerCallbacks — read-only callbacks (getSnapshot, getLayer) passed to adapters on registration
• core: setTimeInfo, onTimeInfoChanged, and enabled on LayerManager
• leaflet: Initial Leaflet adapter for @ulm/core, including a factory for creating a Leaflet-backed layer manager
• leaflet: Type-safe bindings between Leaflet layers and the @ulm/core layer configuration