apieceofbart · September 9, 2019 14:04 · Aug 2, 2019 · Aug 2, 2019
diff --git a/example.actions.ts b/example.actions.ts
@@ -2,7 +2,7 @@ import { ThunkAction } from '.../redux-thunk-promise';
 import { AppState } from 'store/';
 import { FETCH, FetchAction } from './types';
 
-export const fetchFoo = (): ThunkAction<void, AppState, null, FetchAction> =>
+export const fetchFoo = (): ThunkAction<void, AppState> =>
   (dispatch, getState) => {
     if (...) {
         dispatch({

diff --git a/redux-thunk-promise.d.ts b/redux-thunk-promise.d.ts
@@ -1,8 +1,6 @@
 // https://github.com/pburtchaell/redux-promise-middleware/issues/253
 
-import { Action } from 'redux';
 import { AsyncAction as OrigAsyncAction } from 'redux-promise-middleware';
-import { ThunkDispatch as OrigThunkDispatch } from 'redux-thunk';
 
 // -----------------------------------
 // redux-promise-middleware extension
@@ -17,16 +15,16 @@ declare type AsyncPayload<R = any> =
       data?: any;
     };
 
-export declare interface AsyncAction<R> extends OrigAsyncAction {
-  payload?: AsyncPayload<R>;
+export declare interface AsyncAction<R = any> extends OrigAsyncAction {
+  payload: AsyncPayload<R>;
 }
 
 type AsyncActionResult<A> = A extends AsyncAction<infer R> ? R : never;
 
-export type AsyncFulfilledAction<A extends AsyncAction, Type = string> = Omit<
-  A,
-  'type' | 'payload'
-> & {
+export type AsyncFulfilledAction<
+  A extends AsyncAction,
+  Type extends string = string
+> = Omit<A, 'type' | 'payload'> & {
   type: Type;
   payload: AsyncActionResult<A>;
 };
@@ -36,17 +34,24 @@ type FulfilledDispatchResult<A extends AsyncAction> = {
   value: AsyncActionResult<A>;
 };
 
+export type AsyncDispatchReturns<T> = T extends AsyncAction
+  ? Promise<FulfilledDispatchResult<T>>
+  : T;
+
 // ----------------------
 // redux-thunk extension
 // ----------------------
 
-export declare interface ThunkDispatch<S, E, A extends Action>
-  extends OrigThunkDispatch<S, E, A> {
-  <A extends AsyncAction>(asyncAction: A): Promise<FulfilledDispatchResult<A>>;
+export type ThunkDispatchReturns<S, E, A> = A extends ThunkAction<infer R, S, E>
+  ? R
+  : A;
+
+export interface ThunkDispatch<S, E> {
+  <A>(action: A): AsyncDispatchReturns<ThunkDispatchReturns<S, E, A>>;
 }
 
-export declare type ThunkAction<R, S, E, A extends Action> = (
-  dispatch: ThunkDispatch<S, E, A>,
+export declare type ThunkAction<R, S, E = null> = (
+  dispatch: ThunkDispatch<S, E>,
   getState: () => S,
   extraArgument: E,
-) => R;
+) => R;
diff --git a/example.action-types.ts b/example.action-types.ts
@@ -0,0 +1,17 @@
+import { AsyncAction, AsyncFulfilledAction } from '.../redux-thunk-promise';
+
+export const FETCH = '.../FETCH';
+export const FETCH_PENDING = '.../FETCH_PENDING';
+export const FETCH_FULFILLED = '.../FETCH_FULFILLED';
+export const FETCH_REJECTED = '.../FETCH_REJECTED';
+
+export interface FetchAction extends AsyncAction<ApiResult> {
+  type: typeof FETCH;
+}
+
+export type FetchFulfilledAction = AsyncFulfilledAction<
+  FetchAction,
+  typeof FETCH_FULFILLED
+>;
+
+export type FooAction = FetchAction | FetchFulfilledAction | ...;
diff --git a/example.actions.ts b/example.actions.ts
@@ -0,0 +1,15 @@
+import { ThunkAction } from '.../redux-thunk-promise';
+import { AppState } from 'store/';
+import { FETCH, FetchAction } from './types';
+
+export const fetchFoo = (): ThunkAction<void, AppState, null, FetchAction> =>
+  (dispatch, getState) => {
+    if (...) {
+        dispatch({
+          type: FETCH,
+          payload: api.list(), // `api.list` is `() => Promise<ApiResult>`
+        }).then(({ value }) => {
+          // value is ApiResult
+        });
+    }
+  };
diff --git a/redux-thunk-promise.d.ts b/redux-thunk-promise.d.ts
@@ -0,0 +1,52 @@
+// https://github.com/pburtchaell/redux-promise-middleware/issues/253
+
+import { Action } from 'redux';
+import { AsyncAction as OrigAsyncAction } from 'redux-promise-middleware';
+import { ThunkDispatch as OrigThunkDispatch } from 'redux-thunk';
+
+// -----------------------------------
+// redux-promise-middleware extension
+// -----------------------------------
+
+declare type AsyncFunction<R = any> = () => Promise<R>;
+declare type AsyncPayload<R = any> =
+  | Promise<R>
+  | AsyncFunction<R>
+  | {
+      promise: Promise<R> | AsyncFunction<R>;
+      data?: any;
+    };
+
+export declare interface AsyncAction<R> extends OrigAsyncAction {
+  payload?: AsyncPayload<R>;
+}
+
+type AsyncActionResult<A> = A extends AsyncAction<infer R> ? R : never;
+
+export type AsyncFulfilledAction<A extends AsyncAction, Type = string> = Omit<
+  A,
+  'type' | 'payload'
+> & {
+  type: Type;
+  payload: AsyncActionResult<A>;
+};
+
+type FulfilledDispatchResult<A extends AsyncAction> = {
+  action: AsyncFulfilledAction<A>;
+  value: AsyncActionResult<A>;
+};
+
+// ----------------------
+// redux-thunk extension
+// ----------------------
+
+export declare interface ThunkDispatch<S, E, A extends Action>
+  extends OrigThunkDispatch<S, E, A> {
+  <A extends AsyncAction>(asyncAction: A): Promise<FulfilledDispatchResult<A>>;
+}
+
+export declare type ThunkAction<R, S, E, A extends Action> = (
+  dispatch: ThunkDispatch<S, E, A>,
+  getState: () => S,
+  extraArgument: E,
+) => R;