refactor(bundle-size): extract dummy infrastructure + auto-install via getRootDummyInputs by layershifter · Pull Request #548 · microsoft/tabster

layershifter · 2026-05-11T13:59:54Z

Summary

Extracts all dummy-input infrastructure into its own modules and wires it up as opt-in via getRootDummyInputs(tabster):

RootDummyManager.ts — formerly inline in Root.ts.
MoverDummyManager.ts, GroupperDummyManager.ts, ModalizerDummyManager.ts — formerly inline per-feature dummy logic.
getRootDummyInputs(tabster) — the public opt-in. Registers the root factory, creates _dummyObserver, installs moveOutOfRoot (phantom-dummy routing), and (when controlTab or rootDummyInputs is on) calls root.addDummyInputs().

To preserve the existing public contract (controlTab: true is the documented default), createTabster auto-invokes getRootDummyInputs when controlTab=true. Consumers can pass controlTab: false to opt out entirely — in that mode, the dummy code can be tree-shaken when no feature needs phantom-dummy routing.

Per-feature dummy managers are direct-imported in Mover/Groupper/Modalizer, gated on tabster._dummyObserver.

Also drops _forceDummy bookkeeping from Root.

Includes the getModalizerWithDummyInputs bundle-size fixture (deferred from #538 because it imports the new getRootDummyInputs export).

Stack context

Stacked on top of #547. Net new in this PR: the dummy infrastructure extraction + the auto-install wiring + _forceDummy removal + the deferred fixture.

\`patch-package\` postinstall hook applies three changes to keyborg@2.14.0 covering both the ESM (\`dist/index.js\`) and CJS (\`dist/index.cjs\`) bundles: 1. \`event.details = details\` — drop the \`@deprecated\` alias of \`event.detail\`. Tabster reads \`e.detail\` exclusively (verified across src/State/FocusedElement.ts and the rest of the codebase). 2. \`triggerKeys\` / \`dismissKeys\` props + the supporting \`shouldDismiss\` / \`scheduleDismiss\` / \`dismissTimer\` machinery. Tabster only ever calls \`createKeyborg(getWindow())\` with no props. 3. \`canOverrideNativeFocus\` runtime probe. Replaces the \`_canOverrideNativeFocus\` flag with the implicit-true assumption modern browsers (everything since IE9) already satisfy. The conditional \`details.isFocusedProgrammatically\` write becomes unconditional — semantically identical when override works. Bundle deltas (createTabster default-mode): keyborg slice: 3.71 → 3.12 kB (-590 B, -16%) createTabster: 30.78 → 30.18 kB (-600 B) getModalizer: 38.47 → 37.87 kB (-600 B) getMover: 44.54 → 43.94 kB (-600 B) getCrossOrigin: 89.64 → 89.04 kB (-600 B) allExports: 92.09 → 91.50 kB (-590 B) Tests pass: 3 pre-existing failures, no regressions across default, uncontrolled, and root-dummy-inputs modes. Stop-gap until upstream microsoft/keyborg can release the same trims (the changes belong there, not as a Tabster-side fork). Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Converts the `Subscribable<A, B>` abstract class and its consumers to factory functions returning plain objects. - `Subscribable` → `createSubscribable<A,B>()` factory returning a `SubscribableCore` interface. The public surface (subscribe/ subscribeFirst/unsubscribe) matches `Types.Subscribable`; setVal/ getVal/trigger are exposed for the composing factory only. - `KeyboardNavigationState` class → `createKeyboardNavigationState` factory. - `FocusedElementState` class → `createFocusedElementState` factory. `FocusedElementState` is preserved as a const namespace for the `forgetMemorized` and `findNextTabbable` static helpers. - `ObservedElementAPI` class → `createObservedElementAPI` factory. - `CrossOriginFocusedElementState` class → `createCrossOriginFocusedElementState` factory, with `setVal` static kept under same-named const namespace. - `CrossOriginObservedElementState` class → `createCrossOriginObservedElementState` factory, with `trigger` static kept under same-named const namespace. Also trims `Subscribable` itself: drops the `callCallbacks` helper in favour of the inlined `trigger` closure, and adds `declare` to `TabsterCustomEvent.details` to drop the redundant initializer SWC was emitting. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

DummyInput was 23.6% of the core bundle (the single largest module). Converting the four classes here in one coordinated pass: - DummyInput → createDummyInput - DummyInputManager → createDummyInputManager (interface + factory), with externally-used statics moveWithPhantomDummy and addPhantomDummyWithTarget kept under a same- named const namespace - DummyInputManagerCore → createDummyInputManagerCore. The class's constructor-return-existing-instance trick (used when an element already has dummy inputs from another subsystem) becomes a natural early-return in a factory. - DummyInputObserver → createDummyInputObserver The four DummyManager subclasses (RootDummyManager, ModalizerDummyManager, MoverDummyManager, GroupperDummyManager) are migrated from `extends DummyInputManager` to composing `createDummyInputManager` and calling `manager.setHandlers(...)` directly. They become free functions (createRootDummyManager etc.) returning the same DummyInputManager interface, so the consuming `dummyManager` field on Root/Modalizer/Mover/ Groupper is now typed as the interface rather than the subclass. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Class scaffolding (constructor + private field declarations + this-binding on arrow methods) doesn't mangle as well as plain top-level functions and closures. Switching RestorerAPI to a factory shaves ~570 B minified / ~45 B gzipped on getRestorer. Pattern: closures replace private fields; the returned object exposes only the public methods the interface requires. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Static methods (getDeloser, getHistory, forceRestoreFocus) are kept under a same-named const namespace, so external call sites in CrossOrigin.ts continue to work unchanged. The internal state needed by those statics is exposed via an internal interface with _-prefixed accessors. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

…actory conversions Apply post-cherry-pick fixes across all 8 converted API factories: - Use addListener/removeListener helpers (PR4) instead of direct addEventListener - Use focusedElementState method calls instead of missing free-function exports - Expose _grouppers/_modalizers as internal getters for test compatibility - Add _grouppers and _modalizers to GroupperAPIInternal/ModalizerAPIInternal types - Exclude generated bundle-size/.readable/ and .claude/ from prettier checks Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

…urface Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

…for tree-shaking Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

…a getRootDummyInputs

github-actions · 2026-05-11T14:01:06Z

📊 Bundle size report

Package & Exports	Baseline (minified/GZIP)	PR	Change
`tabster` all exports	`113.84 kB` `30.937 kB`	`93.848 kB` `28.791 kB`	`-19.992 kB` `-2.146 kB`
`tabster` createTabster (core)	`39.761 kB` `11.892 kB`	`29.793 kB` `10.136 kB`	`-9.968 kB` `-1.756 kB`
`tabster` findAllFocusable	`0 B` `0 B`	`29.861 kB` `10.157 kB`	🆕 New entry
`tabster` findLastFocusable	`0 B` `0 B`	`29.85 kB` `10.159 kB`	🆕 New entry
`tabster` findNextFocusable	`0 B` `0 B`	`29.836 kB` `10.151 kB`	🆕 New entry
`tabster` findPrevFocusable	`0 B` `0 B`	`29.85 kB` `10.157 kB`	🆕 New entry
`tabster` getCrossOrigin	`110.623 kB` `30.244 kB`	`91.366 kB` `28.072 kB`	`-19.257 kB` `-2.172 kB`
`tabster` getDeloser	`49.268 kB` `14.234 kB`	`38.548 kB` `12.591 kB`	`-10.72 kB` `-1.643 kB`
`tabster` getGroupper	`47 kB` `13.593 kB`	`37.106 kB` `12.235 kB`	`-9.894 kB` `-1.358 kB`
`tabster` getModalizer	`49.072 kB` `14.378 kB`	`38.379 kB` `12.683 kB`	`-10.693 kB` `-1.695 kB`
`tabster` getModalizer (with dummy inputs)	`0 B` `0 B`	`38.387 kB` `12.685 kB`	🆕 New entry
`tabster` getMover	`54.653 kB` `15.887 kB`	`44.042 kB` `14.327 kB`	`-10.611 kB` `-1.56 kB`
`tabster` getObservedElement	`45.564 kB` `13.484 kB`	`34.278 kB` `11.636 kB`	`-11.286 kB` `-1.848 kB`
`tabster` getOutline	`48.867 kB` `14.216 kB`	`36.225 kB` `12.109 kB`	`-12.642 kB` `-2.107 kB`
`tabster` getRestorer	`42.518 kB` `12.52 kB`	`32.214 kB` `10.866 kB`	`-10.304 kB` `-1.654 kB`

_{🤖 This report was generated against a579ebbd50e37f1565551549fe57bbc9ddafab64}

layershifter and others added 19 commits May 11, 2026 11:41

chore(bundle-size): add fixtures for Focusable find* methods

9112d7a

refactor(bundle-size): drop dead code paths + declare class fields

7a1be1c

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

refactor(bundle-size): use free-function helpers for events and timers

e0fa9ee

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

refactor(bundle-size): convert OutlineAPI class → factory function

fe95178

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

refactor(bundle-size): convert GroupperAPI class → factory function

127475d

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

refactor(bundle-size): convert MoverAPI class → factory function

522c515

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

refactor(bundle-size): convert ModalizerAPI class → factory function

268431e

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

refactor(bundle-size): convert CrossOriginAPI class → factory function

8606f25

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

refactor(bundle-size): convert UncontrolledAPI class → factory function

d3ab201

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

refactor(bundle-size): extract context resolvers + slim TabsterCore s…

1acb7be

…urface Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

refactor(bundle-size): extract Focusable mover/groupper resolver

41ab3b9

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

refactor(bundle-size)!: hoist focusedElement helpers to module-level …

82e5fe0

…for tree-shaking Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

refactor(bundle-size): extract dummy infrastructure + auto-install vi…

4ded9a0

…a getRootDummyInputs

This was referenced May 11, 2026

refactor(bundle-size)!: extract Tab keydown handler into opt-in module #549

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chore(bundle-size): add fixtures for Focusable find* methods #538

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refactor(bundle-size): extract dummy infrastructure + auto-install via getRootDummyInputs#548

refactor(bundle-size): extract dummy infrastructure + auto-install via getRootDummyInputs#548
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layershifter commented May 11, 2026

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github-actions Bot commented May 11, 2026

📊 Bundle size report

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