Add overload for bindActionCreators (#224)

* Add overload for bindActionCreators

* Add ThunkActionDispatch type to use when declaring interfaces

* Fix ThunkActionDispatch: generic should expect to extend a function, not just the return type

Author: RMHonor

index.d.ts

@@ -1,4 +1,10 @@
-import { Middleware, Action, AnyAction } from "redux";
+import {
+  Action,
+  ActionCreatorsMapObject,
+  AnyAction,
+  Dispatch,
+  Middleware,
+} from 'redux';
 
 export interface ThunkDispatch<S, E, A extends Action> {
   <R>(thunkAction: ThunkAction<R, S, E, A>): R;
@@ -11,10 +17,33 @@ export type ThunkAction<R, S, E, A extends Action> = (
   extraArgument: E
 ) => R;
 
+/**
+ * Takes a ThunkAction and returns a function signature which matches how it would appear when processed using
+ * bindActionCreators
+ *
+ * @template T ThunkAction to be wrapped
+ */
+export type ThunkActionDispatch<T extends (...args: any[]) => ThunkAction<any, any, any, any>> = (...args: Parameters<T>)
+  => ReturnType<ReturnType<T>>;
+
 export type ThunkMiddleware<S = {}, A extends Action = AnyAction, E = undefined> = Middleware<ThunkDispatch<S, E, A>, S, ThunkDispatch<S, E, A>>;
 
 declare const thunk: ThunkMiddleware & {
   withExtraArgument<E>(extraArgument: E): ThunkMiddleware<{}, AnyAction, E>
 }
 
 export default thunk;
+
+/**
+ * Redux behaviour changed by middleware, so overloads here
+ */
+declare module 'redux' {
+  /**
+   * Overload for bindActionCreators redux function, returns expects responses
+   * from thunk actions
+   */
+  function bindActionCreators<M extends ActionCreatorsMapObject<any>>(
+    actionCreators: M,
+    dispatch: Dispatch,
+  ): { [N in keyof M]: ReturnType<M[N]> extends ThunkAction<any, any, any, any> ? (...args: Parameters<M[N]>) => ReturnType<ReturnType<M[N]>> : M[N] }
+}

package-lock.json

@@ -68,7 +68,7 @@
     "mocha": "^2.2.5",
     "redux": "~4.0.0",
     "rimraf": "^2.5.2",
-    "typescript": "~2.6.2",
+    "typescript": "^3.1.6",
     "typings-tester": "^0.3.1",
     "webpack": "^1.12.14"
   }

package.json

@@ -1,5 +1,15 @@
-import { createStore, applyMiddleware } from 'redux';
-import thunk, { ThunkAction, ThunkMiddleware, ThunkDispatch } from '../index';
+import {
+  applyMiddleware,
+  bindActionCreators,
+  createStore,
+} from 'redux';
+
+import thunk, {
+  ThunkAction,
+  ThunkActionDispatch,
+  ThunkDispatch,
+  ThunkMiddleware,
+} from '../index';
 
 type State = {
   foo: string;
@@ -50,6 +60,42 @@ function anotherThunkAction(): ThunkResult<string> {
   }
 }
 
+function promiseThunkAction(): ThunkResult<Promise<boolean>> {
+  return async (dispatch, getState) => {
+    dispatch({ type: 'FOO' });
+    return false;
+  }
+}
+
+const standardAction = () => ({ type: 'FOO' });
+
+interface ActionDispatchs {
+  anotherThunkAction: ThunkActionDispatch<typeof anotherThunkAction>;
+  promiseThunkAction: ThunkActionDispatch<typeof promiseThunkAction>;
+  standardAction: typeof standardAction;
+}
+
+// test that bindActionCreators correctly returns actions responses of ThunkActions
+// also ensure standard action creators still work as expected
+const actions: ActionDispatchs = bindActionCreators({
+  anotherThunkAction,
+  promiseThunkAction,
+  standardAction,
+}, store.dispatch);
+
+
+
+actions.anotherThunkAction() === 'hello';
+// typings:expect-error
+actions.anotherThunkAction() === false;
+actions.promiseThunkAction().then((res) => console.log(res));
+// typings:expect-error
+actions.promiseThunkAction().prop;
+actions.standardAction().type;
+// typings:expect-error
+actions.standardAction().other;
+
+
 store.dispatch({ type: 'FOO' });
 // typings:expect-error
 store.dispatch({ type: 'BAR' })
@@ -85,5 +131,5 @@ const callDispatchAsync_specificActions = (dispatch: ThunkDispatch<State, undefi
 const callDispatchAny = (dispatch: ThunkDispatch<State, undefined, Actions>) => {
   const asyncThunk = (): any => () => ({} as Promise<void>);
   dispatch(asyncThunk()) // result is any
-    .then(() => console.log('done')) 
-}
+    .then(() => console.log('done'))
+}