feat: allow empty state option to make it easy to group stores

README.md

@@ -287,7 +287,6 @@ import { useCartStore } from './cart'
 
 export const useSharedStore = createStore({
   id: 'shared',
-  state: () => ({}),
   getters: {
     summary() {
       const user = useUserStore()

__tests__/store.spec.ts

@@ -29,6 +29,29 @@ describe('Store', () => {
     })
   })
 
+  it('can be reset', () => {
+    const store = useStore()
+    store.state.a = false
+    const spy = jest.fn()
+    store.subscribe(spy)
+    store.reset()
+    store.state.nested.foo = 'bar'
+    expect(spy).not.toHaveBeenCalled()
+    expect(store.state).toEqual({
+      a: true,
+      nested: {
+        foo: 'bar',
+        a: { b: 'string' },
+      },
+    })
+  })
+
+  it('can create an empty state if no state option is provided', () => {
+    const store = createStore({ id: 'some' })()
+
+    expect(store.state).toEqual({})
+  })
+
   it('can hydrate the state', () => {
     setActiveReq({})
     const useStore = createStore({
@@ -93,4 +116,39 @@ describe('Store', () => {
     store.state.nested.a.b = 'hey'
     expect(store2.state.nested.a.b).toBe('string')
   })
+
+  it('subscribe to changes', () => {
+    const store = useStore()
+    const spy = jest.fn()
+    store.subscribe(spy)
+
+    store.state.a = false
+
+    expect(spy).toHaveBeenCalledWith(
+      {
+        payload: {},
+        storeName: 'main',
+        type: expect.stringContaining('in place'),
+      },
+      store.state
+    )
+  })
+
+  it('subscribe to changes done via patch', () => {
+    const store = useStore()
+    const spy = jest.fn()
+    store.subscribe(spy)
+
+    const patch = { a: false }
+    store.patch(patch)
+
+    expect(spy).toHaveBeenCalledWith(
+      {
+        payload: patch,
+        storeName: 'main',
+        type: expect.stringContaining('patch'),
+      },
+      store.state
+    )
+  })
 })

src/store.ts

@@ -8,7 +8,6 @@ import {
   StoreWithGetters,
   StoreGetter,
   NonNullObject,
-  StoreReactiveGetters,
 } from './types'
 import { useStoreDevtools } from './devtools'
 
@@ -61,25 +60,6 @@ export type Store<
   A extends Record<string, StoreAction>
 > = StoreWithState<Id, S> & StoreWithGetters<S, G> & StoreWithActions<A>
 
-export type WrapStoreWithId<
-  S extends Store<string, StateTree, any, any>
-> = S extends Store<infer Id, infer S, infer G, infer A>
-  ? {
-      [k in Id]: Store<Id, S, G, A>
-    }
-  : never
-
-export type ExtractGettersFromStore<S> = S extends Store<
-  any,
-  infer S,
-  infer G,
-  any
->
-  ? {
-      [k in keyof G]: ReturnType<G[k]>
-    }
-  : never
-
 export type PiniaStore<
   P extends Record<string, Store<any, any, any, any>>
 > = P extends Record<infer name, any>
@@ -107,7 +87,7 @@ export function buildStore<
   A extends Record<string, StoreAction>
 >(
   id: Id,
-  buildState: () => S,
+  buildState = () => ({} as S),
   getters: G = {} as G,
   actions: A = {} as A,
   initialState?: S | undefined
@@ -281,7 +261,7 @@ export function createStore<
   A extends Record<string, StoreAction>
 >(options: {
   id: Id
-  state: () => S
+  state?: () => S
   getters?: G
   // allow actions use other actions
   actions?: A & ThisType<A & StoreWithState<Id, S> & StoreWithGetters<S, G>>