From c457dd94ee5b69e4776a247a660729a16c5c6682 Mon Sep 17 00:00:00 2001
From: Gregory Beaver <greg.beaver.cello@gmail.com>
Date: Thu, 29 Aug 2019 13:26:40 -0400
Subject: [PATCH 1/2] convert applyMiddleware.js to typescript

---
 ...{applyMiddleware.js => applyMiddleware.ts} | 20 ++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)
 rename src/{applyMiddleware.js => applyMiddleware.ts} (72%)

diff --git a/src/applyMiddleware.js b/src/applyMiddleware.ts
similarity index 72%
rename from src/applyMiddleware.js
rename to src/applyMiddleware.ts
index 3bfc647b45..3837181241 100644
--- a/src/applyMiddleware.js
+++ b/src/applyMiddleware.ts
@@ -1,4 +1,11 @@
 import compose from './compose'
+import {
+  Middleware,
+  StoreEnhancer,
+  StoreCreator,
+  Dispatch,
+  AnyAction
+} from '..'
 
 /**
  * Creates a store enhancer that applies middleware to the dispatch method
@@ -16,10 +23,12 @@ import compose from './compose'
  * @param {...Function} middlewares The middleware chain to be applied.
  * @returns {Function} A store enhancer applying the middleware.
  */
-export default function applyMiddleware(...middlewares) {
-  return createStore => (...args) => {
-    const store = createStore(...args)
-    let dispatch = () => {
+export default function applyMiddleware(
+  ...middlewares: Middleware[]
+): StoreEnhancer {
+  return (createStore: StoreCreator) => (reducer: any, ...args) => {
+    const store = createStore(reducer, ...args)
+    let dispatch: Dispatch = () => {
       throw new Error(
         'Dispatching while constructing your middleware is not allowed. ' +
           'Other middleware would not be applied to this dispatch.'
@@ -28,7 +37,8 @@ export default function applyMiddleware(...middlewares) {
 
     const middlewareAPI = {
       getState: store.getState,
-      dispatch: (...args) => dispatch(...args)
+      dispatch: (action: AnyAction, ...args: any[]) =>
+        (dispatch as any)(action, ...args)
     }
     const chain = middlewares.map(middleware => middleware(middlewareAPI))
     dispatch = compose(...chain)(store.dispatch)

From b8f113bbb854a4d1e2c59bd8b31d05fd31019ad6 Mon Sep 17 00:00:00 2001
From: Gregory Beaver <greg.beaver.cello@gmail.com>
Date: Thu, 29 Aug 2019 13:45:38 -0400
Subject: [PATCH 2/2] vastly improve the definition of middleware types

---
 index.d.ts             |  2 +-
 src/applyMiddleware.ts | 14 +++++++++-----
 2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/index.d.ts b/index.d.ts
index d31a15ffea..db64dd5e3c 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -211,7 +211,7 @@ export function combineReducers<M extends ReducersMapObject<any, any>>(
  *   dispatched.
  */
 export interface Dispatch<A extends Action = AnyAction> {
-  <T extends A>(action: T): T
+  <T extends A>(action: T, ...extraArgs: any[]): T
 }
 
 /**
diff --git a/src/applyMiddleware.ts b/src/applyMiddleware.ts
index 3837181241..68e698e8f0 100644
--- a/src/applyMiddleware.ts
+++ b/src/applyMiddleware.ts
@@ -3,8 +3,10 @@ import {
   Middleware,
   StoreEnhancer,
   StoreCreator,
+  AnyAction,
+  Reducer,
   Dispatch,
-  AnyAction
+  MiddlewareAPI
 } from '..'
 
 /**
@@ -26,7 +28,10 @@ import {
 export default function applyMiddleware(
   ...middlewares: Middleware[]
 ): StoreEnhancer {
-  return (createStore: StoreCreator) => (reducer: any, ...args) => {
+  return (createStore: StoreCreator) => <S, A extends AnyAction>(
+    reducer: Reducer<S, A>,
+    ...args: any[]
+  ) => {
     const store = createStore(reducer, ...args)
     let dispatch: Dispatch = () => {
       throw new Error(
@@ -35,10 +40,9 @@ export default function applyMiddleware(
       )
     }
 
-    const middlewareAPI = {
+    const middlewareAPI: MiddlewareAPI = {
       getState: store.getState,
-      dispatch: (action: AnyAction, ...args: any[]) =>
-        (dispatch as any)(action, ...args)
+      dispatch: (action, ...args) => dispatch(action, ...args)
     }
     const chain = middlewares.map(middleware => middleware(middlewareAPI))
     dispatch = compose(...chain)(store.dispatch)