export AsyncThunkPayloadCreator type (#512)

* export AsyncThunkPayloadCreator type

* Fix typo in type name

Co-authored-by: Mark Erikson <mark@isquaredsoftware.com>

Author: phryneas

etc/redux-toolkit.api.md

@@ -59,6 +59,12 @@ export interface ActionReducerMapBuilder<State> {
 // @public @deprecated
 export type Actions<T extends keyof any = string> = Record<T, Action>;
 
+// @public
+export type AsyncThunkPayloadCreator<Returned, ThunkArg = void, ThunkApiConfig extends AsyncThunkConfig = {}> = (arg: ThunkArg, thunkAPI: GetThunkAPI<ThunkApiConfig>) => AsyncThunkPayloadCreatorReturnValue<Returned, ThunkApiConfig>;
+
+// @public
+export type AsyncThunkPayloadCreatorReturnValue<Returned, ThunkApiConfig extends AsyncThunkConfig> = Promise<Returned | RejectWithValue<GetRejectValue<ThunkApiConfig>>> | Returned | RejectWithValue<GetRejectValue<ThunkApiConfig>>;
+
 // @public
 export type CaseReducer<S = any, A extends Action = AnyAction> = (state: Draft<S>, action: A) => S | void;
 
@@ -105,7 +111,7 @@ export function createAction<P = void, T extends string = string>(type: T): Payl
 export function createAction<PA extends PrepareAction<any>, T extends string = string>(type: T, prepareAction: PA): PayloadActionCreator<ReturnType<PA>['payload'], T, PA>;
 
 // @public (undocumented)
-export function createAsyncThunk<Returned, ThunkArg = void, ThunkApiConfig extends AsyncThunkConfig = {}>(type: string, payloadCreator: (arg: ThunkArg, thunkAPI: GetThunkAPI<ThunkApiConfig>) => Promise<Returned | RejectWithValue<GetRejectValue<ThunkApiConfig>>> | Returned | RejectWithValue<GetRejectValue<ThunkApiConfig>>): ((arg: ThunkArg) => (dispatch: GetDispatch<ThunkApiConfig>, getState: () => GetState<ThunkApiConfig>, extra: GetExtra<ThunkApiConfig>) => Promise<PayloadAction<Returned, string, {
+export function createAsyncThunk<Returned, ThunkArg = void, ThunkApiConfig extends AsyncThunkConfig = {}>(type: string, payloadCreator: AsyncThunkPayloadCreator<Returned, ThunkArg, ThunkApiConfig>): ((arg: ThunkArg) => (dispatch: GetDispatch<ThunkApiConfig>, getState: () => GetState<ThunkApiConfig>, extra: GetExtra<ThunkApiConfig>) => Promise<PayloadAction<Returned, string, {
     arg: ThunkArg;
     requestId: string;
 }, never> | PayloadAction<GetRejectValue<ThunkApiConfig> | undefined, string, {

src/createAsyncThunk.ts

@@ -102,6 +102,33 @@ type GetRejectValue<ThunkApiConfig> = ThunkApiConfig extends {
 }
   ? RejectValue
   : unknown
+/**
+ * A type describing the return value of the `payloadCreator` argument to `createAsyncThunk`.
+ * Might be useful for wrapping `createAsyncThunk` in custom abstractions.
+ *
+ * @public
+ */
+export type AsyncThunkPayloadCreatorReturnValue<
+  Returned,
+  ThunkApiConfig extends AsyncThunkConfig
+> =
+  | Promise<Returned | RejectWithValue<GetRejectValue<ThunkApiConfig>>>
+  | Returned
+  | RejectWithValue<GetRejectValue<ThunkApiConfig>>
+/**
+ * A type describing the `payloadCreator` argument to `createAsyncThunk`.
+ * Might be useful for wrapping `createAsyncThunk` in custom abstractions.
+ *
+ * @public
+ */
+export type AsyncThunkPayloadCreator<
+  Returned,
+  ThunkArg = void,
+  ThunkApiConfig extends AsyncThunkConfig = {}
+> = (
+  arg: ThunkArg,
+  thunkAPI: GetThunkAPI<ThunkApiConfig>
+) => AsyncThunkPayloadCreatorReturnValue<Returned, ThunkApiConfig>
 
 /**
  *
@@ -116,13 +143,7 @@ export function createAsyncThunk<
   ThunkApiConfig extends AsyncThunkConfig = {}
 >(
   type: string,
-  payloadCreator: (
-    arg: ThunkArg,
-    thunkAPI: GetThunkAPI<ThunkApiConfig>
-  ) =>
-    | Promise<Returned | RejectWithValue<GetRejectValue<ThunkApiConfig>>>
-    | Returned
-    | RejectWithValue<GetRejectValue<ThunkApiConfig>>
+  payloadCreator: AsyncThunkPayloadCreator<Returned, ThunkArg, ThunkApiConfig>
 ) {
   type RejectedValue = GetRejectValue<ThunkApiConfig>
 

src/index.ts

@@ -96,6 +96,8 @@ export {
 } from './entities/models'
 
 export {
+  AsyncThunkPayloadCreatorReturnValue,
+  AsyncThunkPayloadCreator,
   createAsyncThunk,
   unwrapResult,
   SerializedError