refactor(combo): overhaul selection, data pipeline, and component architecture

[rkaraivanov]

Description

Major refactoring of the IgcComboComponent and its supporting infrastructure to improve maintainability, correctness, and adherence to project conventions.

• combo.ts

• Inherits from IgcBaseComboBoxComponent instead of bare LitElement, sharing open/close lifecycle (_show, _hide) with picker components.

• Removed the SelectionController — selection state (_selected: Set<T>) is now managed directly inside the component for a simpler, single-source-of-truth model.

• Replaced @watch('open') decorator with willUpdate() lifecycle hook.

• Replaced @queryAssignedElements with addSlotController / setSlots for slot detection (no more inputPrefix / inputSuffix public properties).

• Form value serialization moved into the setFormValue transformer on createFormValueState — removes the separate _setFormValue() override.

• _setDefaultValue now handles invalid JSON gracefully instead of throwing.

• firstUpdated removed; initialization is handled by willUpdate / willUpdate data-sync guard for the delayed-data scenario.

• Added _syncSelectionFromValue() (value → Set) and _syncValueFromSelection() (Set → form value) for explicit one-way data flow.

• Added _resolveItems(), _resolveItemValue(), _getValues() private helpers.

• All internal render helpers and event handlers renamed to _camelCase convention (e.g., renderMainInput → _renderMainInput, handleMainInput → _handleMainInput).

• groupKey / groupSorting setters removed — now simple @property declarations; pipeline invalidation driven by willUpdate.

• filteringOptions and disableFiltering setters simplified.

• label and placeholder changed from ! non-null asserted to optional (?).

• placeholderSearch setter typed as string | undefined.

• Added Iterator.from usage for lazy mapping/filtering of selections.

• controllers/data.ts — DataController → DataState

• Introduced a dirty flag pattern: invalidate() marks state as dirty and hostUpdate() runs the pipeline lazily before each render, batching multiple property changes into a single pipeline execution.

• Locale-aware Intl.Collator initialized from host locale; updated via updateLocale(locale).

• dataState is now a read-only accessor.

• Added invalidate() and updateLocale() as explicit public API.

• Internal pipeline methods prefixed with _.

• controllers/navigation.ts

• Removed all // @ts-expect-error: protected access hacks.

• Added interactions config object to decouple hide, show, toggleSelection, select, and clearSelection callbacks — the navigation controller no longer reaches into the combo's protected methods directly.

• _active field is now public (active) so it can be read without casting.

• _getNearestItem rewritten with a for loop (was while with off-by-one risk).

• Navigation mutations now call requestUpdate('_activeIndex', previous) with the old value so Lit schedules targeted updates.

• Keybinding setup moved to the constructor body (was at the end).

• controllers/selection.ts

• Deleted. All selection logic inlined into combo.ts.

• combo-item.ts

• renderCheckbox renamed to _renderCheckbox.

• Switched from nothing conditional to Lit's cache() directive to preserve the checkbox DOM subtree when hideCheckbox toggles.

• connectedCallback marked @internal.

• Missing @attr / @default JSDoc tags added.

• combo-list.ts / combo-header.ts

• Added explicit void return type to register() methods.

• common/mixins/combo-box.ts

• IgcBaseComboBoxLikeComponent renamed to IgcBaseComboBoxComponent (core open/ close behaviour only: open, _show, _hide, _handleAnchorClick, events).

• IgcComboBoxBaseLikeComponent extracted as a new subclass that adds keepOpenOnSelect and keepOpenOnOutsideClick — used by Dropdown, Select, DatePicker, and DateRangePicker.

• Protected event helpers renamed: emitClosing → _emitClosing, etc.

• handleAnchorClick → _handleAnchorClick.

• Utility functions (getItems, getActiveItems, etc.) given explicit return types.

• setInitialSelectionState simplified using last() and direct assignment.

• common/util.ts

• findElementFromEventPath renamed to getElementFromPath with full JSDoc.

• New stopPropagation(event) utility function extracted (used in combo template).

• asArray now uses value == null instead of isDefined(value).

• Cross-component rename: findElementFromEventPath → getElementFromPath Updated all callers: button-group, calendar, carousel, drag, key-bindings, root-click, date-picker, date-range-picker, dropdown, resize-controller, select, stepper, tabs, tile, tree-item.

• Added test: "should handle invalid JSON in value attribute gracefully".

• Removed await list.layoutComplete from keyboard-selection test (no longer needed).

Type of Change

• Refactoring (code improvements without functional changes)

Checklist

• My code follows the project's coding standards
• I have tested my changes locally
• I have updated documentation if needed

[Copilot]

Pull request overview

Major refactor of IgcComboComponent and related infrastructure to simplify selection management, introduce lazy/batched data pipeline execution, and align internal APIs/naming with project conventions.

Changes:

• Refactored combo selection to a component-owned Set with explicit one-way syncing between value and internal selection.
• Replaced DataController with DataState using a dirty-flag + hostUpdate() to batch pipeline execution and support locale-aware collation.
• Renamed findElementFromEventPath → getElementFromPath across the codebase and updated combo-box base behavior (_show/_hide, _handleAnchorClick, event helpers).

Reviewed changes

Copilot reviewed 29 out of 29 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
stories/combo.stories.ts	Reorders Storybook controls/args for open.
src/components/tree/tree-item.ts	Updates event-path lookup helper rename.
src/components/tile-manager/tile.ts	Updates event-path lookup helper rename.
src/components/tabs/tabs.ts	Updates event-path lookup helper rename.
src/components/stepper/stepper.ts	Updates event-path lookup helper rename.
src/components/select/select.ts	Migrates to new combo-box base mixin and _handleAnchorClick naming.
src/components/resize-container/resize-controller.ts	Updates event-path lookup helper rename.
src/components/dropdown/dropdown.ts	Migrates to new combo-box base mixin and _handleAnchorClick naming; updates event-path helper.
src/components/date-range-picker/date-range-picker.ts	Migrates to new combo-box base mixin and _handleAnchorClick naming; updates event-path helper.
src/components/date-picker/date-picker.ts	Migrates to new combo-box base mixin and _handleAnchorClick naming; updates event-path helper.
src/components/common/util.ts	Introduces getElementFromPath + stopPropagation; tweaks asArray nullish handling.
src/components/common/mixins/combo-box.ts	Splits base combo-box behavior into IgcBaseComboBoxComponent + IgcComboBoxBaseLikeComponent; renames protected helpers; adds explicit return types.
src/components/common/controllers/root-click.ts	Updates event-path lookup helper rename.
src/components/common/controllers/key-bindings.ts	Updates event-path lookup helper rename.
src/components/common/controllers/drag.ts	Updates event-path lookup helper rename.
src/components/combo/operations/group.ts	Updates pipeline controller type (DataState).
src/components/combo/operations/filter.ts	Updates pipeline controller type (DataState) and adds explicit return type.
src/components/combo/controllers/selection.ts	Removes selection controller (selection logic moved into combo component).
src/components/combo/controllers/navigation.ts	Refactors navigation to use injected interaction callbacks; removes protected-access hacks; improves nearest-item logic and update scheduling.
src/components/combo/controllers/data.ts	Replaces eager pipeline runs with dirty-flag + lazy pipeline execution in hostUpdate(); adds locale update API.
src/components/combo/combo.ts	Overhauls combo architecture: inherits base combo-box component, inlines selection state, adds explicit sync helpers, updates slot handling and internal naming conventions.
src/components/combo/combo.spec.ts	Adjusts keyboard-selection test timing and adds invalid-JSON regression test.
src/components/combo/combo-list.ts	Adds explicit void return type for register().
src/components/combo/combo-item.ts	Renames checkbox renderer, uses cache() to preserve checkbox subtree, and adds missing JSDoc tags/return types.
src/components/combo/combo-header.ts	Adds explicit void return type for register().
src/components/carousel/carousel.ts	Updates event-path lookup helper rename.
src/components/calendar/helpers.ts	Updates event-path lookup helper rename.
src/components/calendar/calendar.ts	Updates event-path lookup helper rename.
src/components/button-group/button-group.ts	Updates event-path lookup helper rename.

[Copilot]

Pull request overview

Copilot reviewed 29 out of 29 changed files in this pull request and generated 1 comment.