Update dependencies and enhance type inference in payload handling. Closes #11

Author: Viktor Pasynok

package-lock.json

@@ -10,10 +10,11 @@
   "author": "Viktor Pasynok",
   "license": "MIT",
   "devDependencies": {
-    "@rslib/core": "0.17.0",
+    "@rslib/core": "0.17.1",
     "@size-limit/preset-small-lib": "11.2.0",
     "@types/react": "^16.8.0 || ^17.0.0 || ^18.0.0 || ^19.0.0",
     "clean-publish": "6.0.1",
+    "patronum": "2.3.0",
     "prettier": "3.6.2",
     "prettier-plugin-organize-imports": "4.3.0",
     "size-limit": "11.2.0",

package.json

@@ -0,0 +1,43 @@
+import { createEffect, createEvent, createStore } from 'effector';
+import { expectTypeOf } from 'vitest';
+import { ExtractWhenPayload } from '../payload';
+
+const event = createEvent<string>();
+const $store = createStore<number>(0);
+const effectFx = createEffect<boolean, void>();
+const effectWithArrayFx = createEffect<string[], void>();
+
+// --- Single Units ---
+
+expectTypeOf<ExtractWhenPayload<typeof event>>().toEqualTypeOf<string>();
+expectTypeOf<ExtractWhenPayload<typeof $store>>().toEqualTypeOf<number>();
+expectTypeOf<ExtractWhenPayload<typeof effectFx>>().toEqualTypeOf<boolean>();
+expectTypeOf<ExtractWhenPayload<typeof effectWithArrayFx>>().toEqualTypeOf<string[]>();
+
+// --- Array of Units ---
+
+// Single type array
+expectTypeOf<ExtractWhenPayload<[typeof event]>>().toEqualTypeOf<string>();
+expectTypeOf<ExtractWhenPayload<[typeof $store]>>().toEqualTypeOf<number>();
+expectTypeOf<ExtractWhenPayload<[typeof effectFx]>>().toEqualTypeOf<boolean>();
+expectTypeOf<ExtractWhenPayload<[typeof effectWithArrayFx]>>().toEqualTypeOf<string[]>();
+
+// Mixed array
+expectTypeOf<
+  ExtractWhenPayload<[typeof event, typeof $store, typeof effectFx, typeof effectWithArrayFx]>
+>().toEqualTypeOf<string | number | boolean | string[]>();
+
+// Mixed array with duplicates
+expectTypeOf<ExtractWhenPayload<[typeof event, typeof event, typeof $store]>>().toEqualTypeOf<string | number>();
+
+// --- Edge Cases ---
+
+// Empty array should resolve to never
+expectTypeOf<ExtractWhenPayload<[]>>().toBeNever();
+
+// Non-unit types should resolve to never
+expectTypeOf<ExtractWhenPayload<string>>().toBeNever();
+expectTypeOf<ExtractWhenPayload<number>>().toBeNever();
+expectTypeOf<ExtractWhenPayload<null>>().toBeNever();
+expectTypeOf<ExtractWhenPayload<undefined>>().toBeNever();
+expectTypeOf<ExtractWhenPayload<{ a: 1 }>>().toBeNever();