fix(types): fix StateCreator subtyping

pmndrs · Oct 22, 2022 · 66f61ac · 66f61ac
1 parent d27ea94
commit 66f61ac
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Showing 8 changed files with 36 additions and 69 deletions.
diff --git a/docs/guides/typescript.md b/docs/guides/typescript.md
@@ -246,9 +246,9 @@ type Logger = <
 ) => StateCreator<T, Mps, Mcs>
 
 type LoggerImpl = <T extends State>(
-  f: PopArgument<StateCreator<T, [], []>>,
+  f: StateCreator<T, [], []>,
   name?: string
-) => PopArgument<StateCreator<T, [], []>>
+) => StateCreator<T, [], []>
 
 const loggerImpl: LoggerImpl = (f, name) => (set, get, store) => {
   type T = ReturnType<typeof f>
@@ -263,12 +263,6 @@ const loggerImpl: LoggerImpl = (f, name) => (set, get, store) => {
 
 export const logger = loggerImpl as unknown as Logger
 
-type PopArgument<T extends (...a: never[]) => unknown> = T extends (
-  ...a: [...infer A, infer _]
-) => infer R
-  ? (...a: A) => R
-  : never
-
 // ---
 
 const useBearStore = create<BearState>()(
@@ -310,9 +304,9 @@ declare module 'zustand' {
 }
 
 type FooImpl = <T extends State, A>(
-  f: PopArgument<StateCreator<T, [], []>>,
+  f: StateCreator<T, [], []>,
   bar: A
-) => PopArgument<StateCreator<T, [], []>>
+) => StateCreator<T, [], []>
 
 const fooImpl: FooImpl = (f, bar) => (set, get, _store) => {
   type T = ReturnType<typeof f>
@@ -325,12 +319,6 @@ const fooImpl: FooImpl = (f, bar) => (set, get, _store) => {
 
 export const foo = fooImpl as unknown as Foo
 
-type PopArgument<T extends (...a: never[]) => unknown> = T extends (
-  ...a: [...infer A, infer _]
-) => infer R
-  ? (...a: A) => R
-  : never
-
 type Write<T extends object, U extends object> = Omit<T, keyof U> & U
 
 type Cast<T, U> = T extends U ? T : U

diff --git a/src/middleware/devtools.ts b/src/middleware/devtools.ts
@@ -141,15 +141,9 @@ declare module '../vanilla' {
 }
 
 type DevtoolsImpl = <T>(
-  storeInitializer: PopArgument<StateCreator<T, [], []>>,
+  storeInitializer: StateCreator<T, [], []>,
   devtoolsOptions?: DevtoolsOptions
-) => PopArgument<StateCreator<T, [], []>>
-
-type PopArgument<T extends (...a: never[]) => unknown> = T extends (
-  ...a: [...infer A, infer _]
-) => infer R
-  ? (...a: A) => R
-  : never
+) => StateCreator<T, [], []>
 
 export type NamedSet<T> = WithDevtools<StoreApi<T>>['setState']
 

diff --git a/src/middleware/immer.ts b/src/middleware/immer.ts
@@ -49,15 +49,9 @@ type StoreImmer<S> = S extends {
     : never
   : never
 
-type PopArgument<T extends (...a: never[]) => unknown> = T extends (
-  ...a: [...infer A, infer _]
-) => infer R
-  ? (...a: A) => R
-  : never
-
 type ImmerImpl = <T>(
-  storeInitializer: PopArgument<StateCreator<T, [], []>>
-) => PopArgument<StateCreator<T, [], []>>
+  storeInitializer: StateCreator<T, [], []>
+) => StateCreator<T, [], []>
 
 const immerImpl: ImmerImpl = (initializer) => (set, get, store) => {
   type T = ReturnType<typeof initializer>

diff --git a/src/middleware/persist.ts b/src/middleware/persist.ts
@@ -319,14 +319,8 @@ type WithPersist<S, A> = S extends { getState: () => infer T }
   : never
 
 type PersistImpl = <T>(
-  storeInitializer: PopArgument<StateCreator<T, [], []>>,
+  storeInitializer: StateCreator<T, [], []>,
   options: PersistOptions<T, T>
-) => PopArgument<StateCreator<T, [], []>>
-
-type PopArgument<T extends (...a: never[]) => unknown> = T extends (
-  ...a: [...infer A, infer _]
-) => infer R
-  ? (...a: A) => R
-  : never
+) => StateCreator<T, [], []>
 
 export const persist = persistImpl as unknown as Persist
diff --git a/src/middleware/redux.ts b/src/middleware/redux.ts
@@ -31,16 +31,10 @@ declare module '../vanilla' {
   }
 }
 
-type PopArgument<T extends (...a: never[]) => unknown> = T extends (
-  ...a: [...infer A, infer _]
-) => infer R
-  ? (...a: A) => R
-  : never
-
 type ReduxImpl = <T, A extends Action>(
   reducer: (state: T, action: A) => T,
   initialState: T
-) => PopArgument<StateCreator<T & ReduxState<A>, [], []>>
+) => StateCreator<T & ReduxState<A>, [], []>
 
 const reduxImpl: ReduxImpl = (reducer, initial) => (set, _get, api) => {
   type S = typeof initial
@@ -53,4 +47,4 @@ const reduxImpl: ReduxImpl = (reducer, initial) => (set, _get, api) => {
 
   return { dispatch: (...a) => (api as any).dispatch(...a), ...initial }
 }
-export const redux = reduxImpl as Redux
+export const redux = reduxImpl as unknown as Redux
diff --git a/src/middleware/subscribeWithSelector.ts b/src/middleware/subscribeWithSelector.ts
@@ -40,14 +40,8 @@ type StoreSubscribeWithSelector<T> = {
 }
 
 type SubscribeWithSelectorImpl = <T extends object>(
-  storeInitializer: PopArgument<StateCreator<T, [], []>>
-) => PopArgument<StateCreator<T, [], []>>
-
-type PopArgument<T extends (...a: never[]) => unknown> = T extends (
-  ...a: [...infer A, infer _]
-) => infer R
-  ? (...a: A) => R
-  : never
+  storeInitializer: StateCreator<T, [], []>
+) => StateCreator<T, [], []>
 
 const subscribeWithSelectorImpl: SubscribeWithSelectorImpl =
   (fn) => (set, get, api) => {

diff --git a/src/vanilla.ts b/src/vanilla.ts
@@ -30,8 +30,7 @@ export type StateCreator<
 > = ((
   setState: Get<Mutate<StoreApi<T>, Mis>, 'setState', undefined>,
   getState: Get<Mutate<StoreApi<T>, Mis>, 'getState', undefined>,
-  store: Mutate<StoreApi<T>, Mis>,
-  $$storeMutations: Mis
+  store: Mutate<StoreApi<T>, Mis>
 ) => U) & { $$storeMutators?: Mos }
 
 // eslint-disable-next-line @typescript-eslint/no-unused-vars, @typescript-eslint/no-empty-interface
@@ -55,12 +54,6 @@ type CreateStoreImpl = <
   initializer: StateCreator<T, [], Mos>
 ) => Mutate<StoreApi<T>, Mos>
 
-type PopArgument<T extends (...a: never[]) => unknown> = T extends (
-  ...a: [...infer A, infer _]
-) => infer R
-  ? (...a: A) => R
-  : never
-
 const createStoreImpl: CreateStoreImpl = (createState) => {
   type TState = ReturnType<typeof createState>
   type Listener = (state: TState, prevState: TState) => void
@@ -94,11 +87,7 @@ const createStoreImpl: CreateStoreImpl = (createState) => {
 
   const destroy: () => void = () => listeners.clear()
   const api = { setState, getState, subscribe, destroy }
-  state = (createState as PopArgument<typeof createState>)(
-    setState,
-    getState,
-    api
-  )
+  state = createState(setState, getState, api)
   return api as any
 }
 

diff --git a/tests/types.test.tsx b/tests/types.test.tsx
@@ -1,4 +1,5 @@
 import create, { StateCreator, StoreApi, UseBoundStore } from 'zustand'
+import { persist } from 'zustand/middleware'
 
 it('can use exposed types', () => {
   type ExampleState = {
@@ -188,3 +189,22 @@ it('state is covariant', () => {
     baz: string
   }> = store
 })
+
+it('StateCreator subtyping', () => {
+  interface State {
+    count: number
+    increment: () => void
+  }
+
+  const foo: () => StateCreator<State, []> = () => (set, get) => ({
+    count: 0,
+    increment: () => {
+      set({ count: get().count + 1 })
+    },
+  })
+
+  create<State>()(persist(foo()))
+
+  const _testSubtyping: StateCreator<State, [['zustand/persist', unknown]]> =
+    {} as StateCreator<State, []>
+})