Encourage use of Action or UnknownAction instead of AnyAction

Author: EskiMojo14

.gitignore

@@ -5,7 +5,6 @@ coverage
 dist
 lib
 es
-types
 
 # Yarn
 .cache

docs/usage/UsageWithTypescript.md

@@ -207,10 +207,10 @@ You could add this to your ESLint config as an example:
 
 [Reducers](../tutorials/fundamentals/part-3-state-actions-reducers.md) are pure functions that receive the current `state` and incoming `action` as arguments, and return a new state.
 
-If you are using Redux Toolkit's `createSlice`, you should rarely need to specifically type a reducer separately. If you do actually write a standalone reducer, it's typically sufficient to declare the type of the `initialState` value, and type the `action` as `AnyAction`:
+If you are using Redux Toolkit's `createSlice`, you should rarely need to specifically type a reducer separately. If you do actually write a standalone reducer, it's typically sufficient to declare the type of the `initialState` value, and type the `action` as `UnknownAction`:
 
 ```ts
-import { AnyAction } from 'redux'
+import { UnknownAction } from 'redux'
 
 interface CounterState {
   value: number
@@ -222,7 +222,7 @@ const initialState: CounterState = {
 
 export default function counterReducer(
   state = initialState,
-  action: AnyAction
+  action: UnknownAction
 ) {
   // logic here
 }
@@ -297,16 +297,16 @@ export type ThunkAction<
 > = (dispatch: ThunkDispatch<S, E, A>, getState: () => S, extraArgument: E) => R
 ```
 
-You will typically want to provide the `R` (return type) and `S` (state) generic arguments. Unfortunately, TS does not allow only providing _some_ generic arguments, so the usual values for the other arguments are `unknown` for `E` and `AnyAction` for `A`:
+You will typically want to provide the `R` (return type) and `S` (state) generic arguments. Unfortunately, TS does not allow only providing _some_ generic arguments, so the usual values for the other arguments are `unknown` for `E` and `UnknownAction` for `A`:
 
 ```ts
-import { AnyAction } from 'redux'
+import { UnknownAction } from 'redux'
 import { sendMessage } from './store/chat/actions'
 import { RootState } from './store'
 import { ThunkAction } from 'redux-thunk'
 
 export const thunkSendMessage =
-  (message: string): ThunkAction<void, RootState, unknown, AnyAction> =>
+  (message: string): ThunkAction<void, RootState, unknown, UnknownAction> =>
   async dispatch => {
     const asyncResp = await exampleAPI()
     dispatch(
@@ -330,7 +330,7 @@ export type AppThunk<ReturnType = void> = ThunkAction<
   ReturnType,
   RootState,
   unknown,
-  AnyAction
+  UnknownAction
 >
 ```
 

docs/usage/migrating-to-modern-redux.mdx

@@ -846,7 +846,7 @@ const store = configureStore({
 // Inferred state type: {todos: TodosState, counter: CounterState}
 export type RootState = ReturnType<typeof store.getState>
 
-// Inferred dispatch type: Dispatch & ThunkDispatch<RootState, undefined, AnyAction>
+// Inferred dispatch type: Dispatch & ThunkDispatch<RootState, undefined, UnknownAction>
 export type AppDispatch = typeof store.dispatch
 // highlight-end
 ```

src/bindActionCreators.ts

@@ -1,12 +1,8 @@
 import { Dispatch } from './types/store'
-import {
-  AnyAction,
-  ActionCreator,
-  ActionCreatorsMapObject
-} from './types/actions'
+import { ActionCreator, ActionCreatorsMapObject, Action } from './types/actions'
 import { kindOf } from './utils/kindOf'
 
-function bindActionCreator<A extends AnyAction = AnyAction>(
+function bindActionCreator<A extends Action>(
   actionCreator: ActionCreator<A>,
   dispatch: Dispatch
 ) {

src/combineReducers.ts

@@ -1,4 +1,4 @@
-import { AnyAction, Action } from './types/actions'
+import { Action } from './types/actions'
 import {
   ActionFromReducersMapObject,
   PreloadedStateShapeFromReducersMapObject,
@@ -156,7 +156,7 @@ export default function combineReducers(reducers: {
 
   return function combination(
     state: StateFromReducersMapObject<typeof reducers> = {},
-    action: AnyAction
+    action: Action
   ) {
     if (shapeAssertionError) {
       throw shapeAssertionError

src/index.ts

@@ -33,7 +33,7 @@ export { ActionCreator, ActionCreatorsMapObject } from './types/actions'
 // middleware
 export { MiddlewareAPI, Middleware } from './types/middleware'
 // actions
-export { Action, AnyAction } from './types/actions'
+export { Action, UnknownAction, AnyAction } from './types/actions'
 
 export {
   createStore,

src/types/actions.ts

@@ -15,7 +15,7 @@
  *
  * @template T the type of the action's `type` tag.
  */
-export interface Action<T = any> {
+export interface Action<T = unknown> {
   type: T
 }
 
@@ -25,6 +25,18 @@ export interface Action<T = any> {
  * This is not part of `Action` itself to prevent types that extend `Action` from
  * having an index signature.
  */
+export interface UnknownAction extends Action {
+  // Allows any extra properties to be defined in an action.
+  [extraProps: string]: unknown
+}
+
+/**
+ * An Action type which accepts any other properties.
+ * This is mainly for the use of the `Reducer` type.
+ * This is not part of `Action` itself to prevent types that extend `Action` from
+ * having an index signature.
+ * @deprecated use Action or UnknownAction instead
+ */
 export interface AnyAction extends Action {
   // Allows any extra properties to be defined in an action.
   [extraProps: string]: any

src/types/reducers.ts

@@ -1,4 +1,4 @@
-import { Action, AnyAction } from './actions'
+import { Action, UnknownAction } from './actions'
 
 /* reducers */
 
@@ -29,7 +29,7 @@ import { Action, AnyAction } from './actions'
  */
 export type Reducer<
   S = any,
-  A extends Action = AnyAction,
+  A extends Action = UnknownAction,
   PreloadedState = S
 > = (state: S | PreloadedState | undefined, action: A) => S
 
@@ -42,7 +42,7 @@ export type Reducer<
  */
 export type ReducersMapObject<
   S = any,
-  A extends Action = AnyAction,
+  A extends Action = UnknownAction,
   PreloadedState = S
 > = keyof PreloadedState extends keyof S
   ? {
@@ -63,7 +63,7 @@ export type StateFromReducersMapObject<M> = M[keyof M] extends
   | Reducer<any, any, any>
   | undefined
   ? {
-      [P in keyof M]: M[P] extends Reducer<infer S> ? S : never
+      [P in keyof M]: M[P] extends Reducer<infer S, any, any> ? S : never
     }
   : never
 
@@ -109,7 +109,7 @@ export type PreloadedStateShapeFromReducersMapObject<M> = M[keyof M] extends
   ? {
       [P in keyof M]: M[P] extends (
         inputState: infer InputState,
-        action: AnyAction
+        action: UnknownAction
       ) => any
         ? InputState
         : never

test/applyMiddleware.spec.ts

@@ -3,7 +3,6 @@ import {
   applyMiddleware,
   Middleware,
   MiddlewareAPI,
-  AnyAction,
   Action,
   Store,
   Dispatch
@@ -128,7 +127,7 @@ describe('applyMiddleware', () => {
     const spy = vi.fn()
     const testCallArgs = ['test']
 
-    interface MultiDispatch<A extends Action = AnyAction> {
+    interface MultiDispatch<A extends Action = Action> {
       <T extends A>(action: T, extraArg?: string[]): T
     }
 

test/combineReducers.spec.ts

@@ -4,7 +4,6 @@ import {
   combineReducers,
   Reducer,
   Action,
-  AnyAction,
   __DO_NOT_USE__ActionTypes as ActionTypes
 } from 'redux'
 import { vi } from 'vitest'
@@ -88,7 +87,7 @@ describe('Utils', () => {
       expect(() => reducer({ counter: 0 }, null)).toThrow(
         /"counter".*an action/
       )
-      expect(() => reducer({ counter: 0 }, {} as unknown as AnyAction)).toThrow(
+      expect(() => reducer({ counter: 0 }, {} as unknown as Action)).toThrow(
         /"counter".*an action/
       )
     })
@@ -117,9 +116,9 @@ describe('Utils', () => {
           throw new Error('Error thrown in reducer')
         }
       })
-      expect(() =>
-        reducer(undefined, undefined as unknown as AnyAction)
-      ).toThrow(/Error thrown in reducer/)
+      expect(() => reducer(undefined, undefined as unknown as Action)).toThrow(
+        /Error thrown in reducer/
+      )
     })
 
     it('allows a symbol to be used as an action type', () => {
@@ -185,7 +184,7 @@ describe('Utils', () => {
 
     it('throws an error on first call if a reducer attempts to handle a private action', () => {
       const reducer = combineReducers({
-        counter(state: number, action: Action<unknown>) {
+        counter(state: number, action: Action) {
           switch (action.type) {
             case 'increment':
               return state + 1
@@ -199,9 +198,9 @@ describe('Utils', () => {
           }
         }
       })
-      expect(() =>
-        reducer(undefined, undefined as unknown as AnyAction)
-      ).toThrow(/"counter".*private/)
+      expect(() => reducer(undefined, undefined as unknown as Action)).toThrow(
+        /"counter".*private/
+      )
     })
 
     it('warns if no reducers are passed to combineReducers', () => {
@@ -223,7 +222,7 @@ describe('Utils', () => {
     it('warns if input state does not match reducer shape', () => {
       const preSpy = console.error
       const spy = vi.fn()
-      const nullAction = undefined as unknown as AnyAction
+      const nullAction = undefined as unknown as Action
       console.error = spy
 
       interface ShapeState {