Mapped type for combineReducers in index.d.ts (#2182)

* Add mapped type for combineReducers in index.d.ts

Updated typescript to 2.1.4
Updated typescript-definition-tester to 0.0.5
Updated typescript tests to use proper import
Added mapped type to index.d.ts

* add strict null check for reducer

Updated Reducer<S> type in index.d.ts
Add strictNullChecks flag to typescript spec

Author: mkusher

index.d.ts

@@ -43,13 +43,13 @@ export interface Action {
  *
  * @template S State object type.
  */
-export type Reducer<S> = <A extends Action>(state: S, action: A) => S;
+export type Reducer<S> = <A extends Action>(state: S | undefined, action: A) => S;
 
 /**
  * Object whose values correspond to different reducer functions.
  */
-export interface ReducersMapObject {
-  [key: string]: Reducer<any>;
+export type ReducersMapObject<S> = {
+  [K in keyof S]: Reducer<S[K]>;
 }
 
 /**
@@ -70,7 +70,7 @@ export interface ReducersMapObject {
  * @returns A reducer function that invokes every reducer inside the passed
  *   object, and builds a state object with the same shape.
  */
-export function combineReducers<S>(reducers: ReducersMapObject): Reducer<S>;
+export function combineReducers<S>(reducers: ReducersMapObject<S>): Reducer<S>;
 
 
 /* store */

package.json

@@ -111,8 +111,8 @@
     "jest": "^18.0.0",
     "rimraf": "^2.3.4",
     "rxjs": "^5.0.0-beta.6",
-    "typescript": "^1.8.0",
-    "typescript-definition-tester": "0.0.4",
+    "typescript": "^2.1.0",
+    "typescript-definition-tester": "0.0.5",
     "webpack": "^1.9.6"
   },
   "npmName": "redux",

test/typescript.spec.js

@@ -6,6 +6,9 @@ describe('TypeScript definitions', function () {
     tt.compileDirectory(
       __dirname + '/typescript',
       fileName => fileName.match(/\.ts$/),
+      {
+        strictNullChecks: true
+      },
       () => done()
     )
   })

test/typescript/actionCreators.ts

@@ -1,7 +1,7 @@
 import {
   ActionCreator, Action, Dispatch,
   bindActionCreators, ActionCreatorsMapObject
-} from "../../index.d.ts";
+} from "../../";
 
 
 interface AddTodoAction extends Action {

test/typescript/actions.ts

@@ -1,4 +1,4 @@
-import {Action as ReduxAction} from "../../index.d.ts";
+import {Action as ReduxAction} from "../../";
 
 
 namespace FSA {

test/typescript/compose.ts

@@ -1,4 +1,4 @@
-import {compose} from "../../index.d.ts";
+import {compose} from "../../";
 
 // copied from DefinitelyTyped/compose-function
 

test/typescript/dispatch.ts

@@ -1,12 +1,12 @@
-import {Dispatch, Action} from "../../index.d.ts";
+import {Dispatch, Action} from "../../";
 
 
 declare const dispatch: Dispatch<any>;
 
 const dispatchResult: Action = dispatch({type: 'TYPE'});
 
 // thunk
-declare module "../../index.d.ts" {
+declare module "../../" {
     export interface Dispatch<S> {
         <R>(asyncAction: (dispatch: Dispatch<S>, getState: () => S) => R): R;
     }

test/typescript/middleware.ts

@@ -1,15 +1,15 @@
 import {
   Middleware, MiddlewareAPI,
   applyMiddleware, createStore, Dispatch, Reducer, Action
-} from "../../index.d.ts";
+} from "../../";
 
-declare module "../../index.d.ts" {
+declare module "../../" {
     export interface Dispatch<S> {
         <R>(asyncAction: (dispatch: Dispatch<S>, getState: () => S) => R): R;
     }
 }
 
-type Thunk<S, O> = (dispatch: Dispatch<S>, getState: () => S) => O;
+type Thunk<S, O> = (dispatch: Dispatch<S>, getState?: () => S) => O;
 
 const thunkMiddleware: Middleware =
   <S>({dispatch, getState}: MiddlewareAPI<S>) =>
@@ -52,7 +52,7 @@ const storeWithThunkMiddleware = createStore(
 );
 
 storeWithThunkMiddleware.dispatch(
-  (dispatch, getState) => {
+  (dispatch: Dispatch<State>, getState: () => State) => {
     const todos: string[] = getState().todos;
     dispatch({type: 'ADD_TODO'})
   }

test/typescript/reducers.ts

@@ -1,7 +1,7 @@
 import {
   Reducer, Action, combineReducers,
   ReducersMapObject
-} from "../../index.d.ts";
+} from "../../";
 
 
 type TodosState = string[];
@@ -47,8 +47,7 @@ type RootState = {
   counter: CounterState;
 }
 
-
-const rootReducer: Reducer<RootState> = combineReducers<RootState>({
+const rootReducer: Reducer<RootState> = combineReducers({
   todos: todosReducer,
   counter: counterReducer,
 })

test/typescript/store.ts

@@ -1,7 +1,7 @@
 import {
   Store, createStore, Reducer, Action, StoreEnhancer, GenericStoreEnhancer,
   StoreCreator, StoreEnhancerStoreCreator, Unsubscribe
-} from "../../index.d.ts";
+} from "../../";
 
 
 type State = {
@@ -22,10 +22,10 @@ const storeWithPreloadedState: Store<State> = createStore(reducer, {
 });
 
 const genericEnhancer: GenericStoreEnhancer = <S>(next: StoreEnhancerStoreCreator<S>) => next;
-const specificEnhencer: StoreEnhancer<State> = next => next;
+const specificEnhancer: StoreEnhancer<State> = next => next;
 
 const storeWithGenericEnhancer: Store<State> = createStore(reducer, genericEnhancer);
-const storeWithSpecificEnhancer: Store<State> = createStore(reducer, specificEnhencer);
+const storeWithSpecificEnhancer: Store<State> = createStore(reducer, specificEnhancer);
 
 const storeWithPreloadedStateAndEnhancer: Store<State> = createStore(reducer, {
   todos: []

yarn.lock

@@ -2719,7 +2719,11 @@ lodash.flatten@^4.4.0:
   version "4.4.0"
   resolved "https://registry.yarnpkg.com/lodash.flatten/-/lodash.flatten-4.4.0.tgz#f31c22225a9632d2bbf8e4addbef240aa765a61f"
 
-lodash.isarguments@^3.0.0, lodash.isarguments@~3.0.7:
+lodash.isarguments@^3.0.0:
+  version "3.1.0"
+  resolved "https://registry.yarnpkg.com/lodash.isarguments/-/lodash.isarguments-3.1.0.tgz#2f573d85c6a24289ff00663b491c1d338ff3458a"
+
+lodash.isarguments@~3.0.7:
   version "3.0.9"
   resolved "https://registry.yarnpkg.com/lodash.isarguments/-/lodash.isarguments-3.0.9.tgz#3c4994a4210f340d49ccfafa62176296207d8675"
 
@@ -4310,17 +4314,17 @@ typedarray@^0.0.6:
   version "0.0.6"
   resolved "https://registry.yarnpkg.com/typedarray/-/typedarray-0.0.6.tgz#867ac74e3864187b1d3d47d996a78ec5c8830777"
 
-[email protected].4:
-  version "0.0.4"
-  resolved "https://registry.yarnpkg.com/typescript-definition-tester/-/typescript-definition-tester-0.0.4.tgz#94b9edc4fe803b47f5f64ff5ddaf8eed1196156c"
+[email protected].5:
+  version "0.0.5"
+  resolved "https://registry.yarnpkg.com/typescript-definition-tester/-/typescript-definition-tester-0.0.5.tgz#91c574d78ea05b81ed81244d50ec30d8240c356f"
   dependencies:
     assertion-error "^1.0.1"
     dts-bundle "^0.2.0"
     lodash "^3.6.0"
 
-typescript@^1.8.0:
-  version "1.8.10"
-  resolved "https://registry.yarnpkg.com/typescript/-/typescript-1.8.10.tgz#b475d6e0dff0bf50f296e5ca6ef9fbb5c7320f1e"
+typescript@^2.1.0:
+  version "2.1.4"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-2.1.4.tgz#b53b69fb841126acb1dd4b397d21daba87572251"
 
 uglify-js@^2.6, uglify-js@~2.7.3:
   version "2.7.5"