Created a plan for supporting any trigger in Interact

.cursor/plans/custom_event_triggers_7d957d99.plan.md

@@ -0,0 +1,233 @@
+---
+name: Custom event triggers
+overview: Allow any DOM event name to be used as a `trigger` in Interact, routing unknown trigger names through the existing `eventTrigger` handler. This requires opening up the `TriggerType` union, adding a handler resolution function, and updating add/remove/types accordingly.
+todos:
+  - id: rename-params
+    content: Rename StateParams -> StateTriggerParams and PointerTriggerParams -> AnimationTriggerParams across all source, rules, and docs files
+    status: pending
+  - id: types
+    content: Update TriggerType and InteractionParamsTypes in src/types.ts (keep eventConfig internal)
+    status: pending
+  - id: handler-resolution
+    content: Add getHandlerForTrigger() to src/handlers/index.ts for dynamic handler resolution
+    status: pending
+  - id: core-add
+    content: Update src/core/add.ts to use getHandlerForTrigger() instead of direct map access
+    status: pending
+  - id: tests
+    content: Add test/eventTrigger.spec.ts with custom event trigger tests
+    status: pending
+  - id: demo
+    content: Create CustomEventDemo.tsx in apps/demo and add to App.tsx
+    status: pending
+  - id: rules
+    content: Add rules/custom-event.md and update rules/full-lean.md
+    status: pending
+  - id: docs
+    content: Update docs/guides/understanding-triggers.md and docs/api/types.md
+    status: pending
+isProject: false
+---
+
+# Custom Event Triggers for Interact
+
+## Architecture Summary
+
+Currently, triggers flow through a static handler map:
+
+```mermaid
+flowchart LR
+    Config["InteractConfig\n(trigger: TriggerType)"] --> AddTS["add.ts\naddInteraction()"]
+    AddTS --> HandlerMap["TRIGGER_TO_HANDLER_MODULE_MAP\n(static object)"]
+    HandlerMap --> ViewEnter["viewEnter handler"]
+    HandlerMap --> EventTrigger["eventTrigger handler"]
+    HandlerMap --> ViewProgress["viewProgress handler"]
+    HandlerMap --> PointerMove["pointerMove handler"]
+    HandlerMap --> AnimEnd["animationEnd handler"]
+    EventTrigger --> Presets["EVENT_TRIGGER_PRESETS\nhover/click/activate/interest"]
+```
+
+The key insight: `hover`, `click`, `activate`, and `interest` are all thin wrappers around `eventTrigger.ts`. They just inject a preset event config (e.g., hover -> `{ enter: ['mouseenter'], leave: ['mouseleave'] }`). For custom triggers, we do the same -- the trigger name itself becomes the event config.
+
+**After the change**, unknown trigger names will be automatically routed through `eventTrigger` using the trigger name as the DOM event:
+
+```mermaid
+flowchart LR
+    Config["trigger: 'dblclick'"] --> AddTS["add.ts\naddInteraction()"]
+    AddTS --> GetHandler["getHandlerForTrigger()"]
+    GetHandler -->|known| HandlerMap["Static map\n(viewEnter, hover, etc.)"]
+    GetHandler -->|unknown| DynHandler["Dynamic handler\neventConfig = trigger name"]
+    DynHandler --> EventTrigger["eventTrigger.add()"]
+```
+
+## Part 0: Rename `StateParams` and `PointerTriggerParams`
+
+Rename across the entire codebase:
+
+- `StateParams` -> `StateTriggerParams`
+- `PointerTriggerParams` -> `AnimationTriggerParams`
+
+**Files affected (source):**
+
+- `src/types.ts` -- type definitions, `EventTriggerParams`, `TriggerParams`, `InteractionParamsTypes`, `IInteractElement.toggleEffect`
+- `src/handlers/index.ts` -- import and `withEventTriggerConfig` signature
+- `src/handlers/eventTrigger.ts` -- import and cast usages in `addEventTriggerHandler`
+- `src/handlers/effectHandlers.ts` -- import and function signatures
+- `src/web/InteractElement.ts` -- import for `toggleEffect` method
+- `src/core/InteractionController.ts` -- import for `toggleEffect` method
+
+**Files affected (rules/docs):**
+
+- `rules/full-lean.md` -- references in params documentation
+- `rules/click.md` -- references to `StateParams.method`
+- `docs/api/types.md` -- type documentation
+- `docs/api/interaction-controller.md` -- `toggleEffect` param type
+- `docs/api/README.md` -- type references
+
+Use `replace_all` for each rename. This is a straightforward find-and-replace with no logic changes.
+
+## Part 1: Type Changes
+
+**File: [src/types.ts](packages/interact/src/types.ts)**
+
+1. Open up `TriggerType` to accept any string while preserving IDE autocomplete for known types:
+
+```typescript
+export type TriggerType =
+  | 'hover'
+  | 'click'
+  | 'viewEnter'
+  | 'pageVisible'
+  | 'animationEnd'
+  | 'viewProgress'
+  | 'pointerMove'
+  | 'activate'
+  | 'interest'
+  | (string & {});
+```
+
+1. `TriggerParams` stays the same -- no `EventTriggerParams` added. `eventConfig` remains internal-only and is never exposed in the public config API. Custom event triggers use `StateTriggerParams | AnimationTriggerParams` (same as `click`/`hover`).
+2. Add a string index signature to `InteractionParamsTypes` (line 252) so that custom trigger keys resolve properly in generics:
+
+```typescript
+export type InteractionParamsTypes = {
+  hover: StateTriggerParams | AnimationTriggerParams;
+  click: StateTriggerParams | AnimationTriggerParams;
+  // ... existing entries ...
+  [key: string]:
+    | StateTriggerParams
+    | AnimationTriggerParams
+    | ViewEnterParams
+    | PointerMoveParams
+    | AnimationEndParams;
+};
+```
+
+## Part 2: Handler Resolution
+
+**File: [src/handlers/index.ts](packages/interact/src/handlers/index.ts)**
+
+Export a `getHandlerForTrigger(trigger)` function that:
+
+- Returns the existing handler module for known triggers (hover, click, viewEnter, etc.)
+- For unknown triggers, returns a dynamically created handler that internally injects the trigger name as `eventConfig` (the internal property) into `eventTrigger.add()`. The user never sees or provides `eventConfig` -- it is derived from the trigger name.
+- All dynamic handlers share `eventTrigger.remove` for cleanup
+
+```typescript
+const KNOWN_HANDLERS = {
+  /* existing map */
+};
+
+export function getHandlerForTrigger(trigger: string) {
+  if (trigger in KNOWN_HANDLERS) {
+    return KNOWN_HANDLERS[trigger as TriggerType];
+  }
+
+  return {
+    add: (source, target, effect, options, interactOptions) => {
+      // eventConfig is internal-only -- derived from the trigger name, never from user params
+      eventTrigger.add(
+        source,
+        target,
+        effect,
+        { ...options, eventConfig: trigger },
+        interactOptions ?? {},
+      );
+    },
+    remove: eventTrigger.remove,
+  };
+}
+
+export default KNOWN_HANDLERS;
+```
+
+## Part 3: Core `add.ts` Changes
+
+**File: [src/core/add.ts](packages/interact/src/core/add.ts)**
+
+- Import `getHandlerForTrigger` from `../handlers`
+- In `addInteraction()` (line 715), replace:
+  `TRIGGER_TO_HANDLER_MODULE_MAP[trigger]?.add(...)` with `getHandlerForTrigger(trigger).add(...)`
+- In `_processSequences()` (line 446) and `_processSequencesForTarget()` (line 536), apply the same replacement for the sequence handler dispatch
+
+## Part 4: Core `remove.ts` -- No Changes Needed
+
+The `removeListItems` function iterates `Object.values(TRIGGER_TO_HANDLER_MODULE_MAP)` and calls `module.remove(element)`. Since `eventTrigger.remove` is already among these values (referenced by hover, click, activate, interest), and since `eventTrigger` uses a single `WeakMap<HTMLElement, Set<HandlerObject>>` for all event-based handlers, calling `eventTrigger.remove` once cleans up ALL event handlers for that element -- including any custom triggers. No changes needed.
+
+## Part 5: Tests
+
+**File: [test/eventTrigger.spec.ts](packages/interact/test/eventTrigger.spec.ts)** (new)
+
+Add tests covering:
+
+- Custom trigger name (e.g., `trigger: 'dblclick'`) routes through `eventTrigger` and attaches the correct DOM listener
+- Custom trigger with `toggle` mode (StateTriggerParams `method: 'toggle'`)
+- Custom trigger with `once` mode (AnimationTriggerParams `type: 'once'`)
+- Cleanup of custom trigger handlers via `remove()`
+- Existing built-in triggers still work as before (regression)
+
+Use the same mock patterns from existing tests (mock `@wix/motion`, create DOM elements, test event dispatch).
+
+## Part 6: Demo Playground
+
+**File: [apps/demo/src/react/components/CustomEventDemo.tsx](apps/demo/src/react/components/CustomEventDemo.tsx)** (new)
+
+Create a demo component showcasing custom event triggers:
+
+- A text input that responds to `input` event with a pulse animation
+- A card that responds to `dblclick` with a flip animation
+- A card that responds to `contextmenu` (right-click) with a shake animation
+- Controls to switch between different custom event types
+- Follow the same pattern as `Playground.tsx`: `useMemo` for config, `useInteractInstance(config)`, `<Interaction>` components
+
+**File: [apps/demo/src/react/App.tsx](apps/demo/src/react/App.tsx)**
+
+- Import and add `<CustomEventDemo />` to the page layout
+
+## Part 7: Rules Update
+
+**File: [rules/custom-event.md](packages/interact/rules/custom-event.md)** (new)
+
+Add a succinct rule file for custom event triggers:
+
+- Explain that any DOM event name can be used as a trigger
+- Show the basic pattern: `trigger: 'dblclick'` with `StateTriggerParams` or `AnimationTriggerParams` (same params as click/hover)
+- 2-3 concise examples
+
+**File: [rules/full-lean.md](packages/interact/rules/full-lean.md)**
+
+- Update the `trigger: TriggerType` section to mention that any DOM event name is accepted as a custom trigger
+- Note that custom triggers use the same params as click/hover (`StateTriggerParams | AnimationTriggerParams`)
+
+## Part 8: Docs Update
+
+**File: [docs/guides/understanding-triggers.md](packages/interact/docs/guides/understanding-triggers.md)**
+
+- Add a new section "Custom Event Triggers" explaining arbitrary DOM events as triggers
+- Update the trigger overview table to include custom event triggers
+- Add examples for `dblclick`, `input`, `contextmenu` using `StateTriggerParams`/`AnimationTriggerParams`
+
+**File: [docs/api/types.md](packages/interact/docs/api/types.md)**
+
+- Update `TriggerType` documentation to reflect it now accepts any string
+- Note that custom triggers accept `StateTriggerParams | AnimationTriggerParams` (same as click/hover)