Add types for package react-combine-reducers (#43749)

* Add types for react-combine-reducer

* Run prettier on react-combine-reducers

* Fix linter issues

types/react-combine-reducers/index.d.ts

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+// Type definitions for react-combine-reducers 1.0
+// Project: https://github.com/ankita1010/react-combine-reducers#readme
+// Definitions by: Raphaël Léger <https://github.com/raphael-leger>
+// Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+// Minimum TypeScript Version: 3.1
+import { Reducer, ReducerState } from 'react';
+
+declare function combineReducers<R extends Reducer<any, any>>(
+    reducers: {
+        [K in keyof ReducerState<R>]: [Reducer<ReducerState<R>[K], any>, ReducerState<R>[K]];
+    },
+): [R, ReducerState<R>];
+export = combineReducers;

types/react-combine-reducers/react-combine-reducers-tests.ts

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+import combineReducers from 'react-combine-reducers';
+
+interface SimpleAction {
+    type: string;
+    payload: any;
+}
+
+interface GreeniesState {
+    fruit: 'apple' | 'pear' | 'kiwi';
+    vegetable: 'carrot' | 'eggplant';
+}
+
+interface ProteinsState {
+    similiCarne: 'tofu' | 'seitan';
+    vegetable: 'bean' | 'artichoke';
+}
+
+interface DrinkState {
+    beverage: 'water' | 'juice';
+    numberOfGlasses: number;
+}
+
+interface DessertState {
+    cake: 'chocolate' | 'cherry';
+    drink: 'tea' | 'coffee';
+}
+
+interface FullMealState {
+    proteins: ProteinsState;
+    greenies: GreeniesState;
+    dessert: DessertState;
+    drink: DrinkState;
+}
+
+type FullMealReducer = (state: FullMealState, action: SimpleAction) => FullMealState;
+
+const proteinsReducer = (proteinsState: ProteinsState, action: SimpleAction) => {
+    switch (action) {
+        default:
+            return proteinsState;
+    }
+};
+
+const drinkReducer = (drinkState: DrinkState, action: SimpleAction) => {
+    switch (action) {
+        default:
+            return drinkState;
+    }
+};
+
+const dessertReducer = (dessertState: DessertState, action: SimpleAction) => {
+    switch (action) {
+        default:
+            return dessertState;
+    }
+};
+
+const greeniesReducer = (greeniesState: GreeniesState, action: SimpleAction) => {
+    switch (action) {
+        default:
+            return greeniesState;
+    }
+};
+
+// $ExpectError
+combineReducers('');
+
+// $ExpectError
+combineReducers<FullMealReducer>({});
+
+// $ExpectError
+combineReducers<FullMealReducer>();
+
+combineReducers<FullMealReducer>({
+    // $ExpectError
+    books: ['The Book Thief'],
+});
+
+combineReducers<FullMealReducer>({
+    // $ExpectError
+    proteins: [100],
+});
+
+combineReducers<FullMealReducer>({
+    // $ExpectError
+    proteins: [3, proteinsReducer],
+});
+
+combineReducers<FullMealReducer>({
+    // $ExpectError
+    proteins: [proteinsReducer, 3],
+});
+
+// $ExpectError
+combineReducers<FullMealReducer>({
+    proteins: [
+        proteinsReducer,
+        {
+            similiCarne: 'tofu',
+            vegetable: 'artichoke',
+        },
+    ],
+});
+
+combineReducers<FullMealReducer>({
+    proteins: [
+        proteinsReducer,
+        {
+            similiCarne: 'tofu',
+            vegetable: 'artichoke',
+        },
+    ],
+    greenies: [
+        // $ExpectError
+        proteinsReducer,
+        {
+            fruit: 'kiwi',
+            vegetable: 'eggplant',
+        },
+    ],
+    drink: [
+        // $ExpectError
+        proteinsReducer,
+        {
+            beverage: 'juice',
+            numberOfGlasses: 2,
+        },
+    ],
+    dessert: [
+        // $ExpectError
+        proteinsReducer,
+        {
+            cake: 'chocolate',
+            drink: 'tea',
+        },
+    ],
+});
+
+const [fullMealReducer, initialMeal] = combineReducers<FullMealReducer>({
+    proteins: [
+        proteinsReducer,
+        {
+            similiCarne: 'tofu',
+            vegetable: 'artichoke',
+        },
+    ],
+    greenies: [
+        greeniesReducer,
+        {
+            fruit: 'kiwi',
+            vegetable: 'eggplant',
+        },
+    ],
+    drink: [
+        drinkReducer,
+        {
+            beverage: 'juice',
+            numberOfGlasses: 2,
+        },
+    ],
+    dessert: [
+        dessertReducer,
+        {
+            cake: 'chocolate',
+            drink: 'tea',
+        },
+    ],
+});
+
+initialMeal.dessert;
+initialMeal.drink;
+initialMeal.proteins;
+initialMeal.greenies;
+
+// $ExpectError
+initialMeal.lamps;
+
+// $ExpectError
+fullMealReducer(3, {});
+
+// $ExpectError
+fullMealReducer({}, {});
+
+fullMealReducer(
+    {
+        proteins: {
+            similiCarne: 'tofu',
+            vegetable: 'artichoke',
+        },
+        greenies: {
+            fruit: 'kiwi',
+            vegetable: 'eggplant',
+        },
+        drink: {
+            beverage: 'juice',
+            numberOfGlasses: 2,
+        },
+        dessert: {
+            cake: 'chocolate',
+            drink: 'tea',
+        },
+    },
+    // $ExpectError
+    67,
+);
+
+fullMealReducer(
+    {
+        proteins: {
+            similiCarne: 'tofu',
+            vegetable: 'artichoke',
+        },
+        greenies: {
+            fruit: 'kiwi',
+            vegetable: 'eggplant',
+        },
+        drink: {
+            beverage: 'juice',
+            numberOfGlasses: 2,
+        },
+        dessert: {
+            cake: 'chocolate',
+            drink: 'tea',
+        },
+    },
+    {
+        type: 'eat',
+        payload: 'everything',
+    },
+);
+
+export { fullMealReducer, initialMeal };

types/react-combine-reducers/tsconfig.json

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+{
+  "compilerOptions": {
+    "module": "commonjs",
+    "lib": [
+      "es6"
+    ],
+    "esModuleInterop": true,
+    "noImplicitAny": true,
+    "noImplicitThis": true,
+    "strictFunctionTypes": true,
+    "strictNullChecks": true,
+    "baseUrl": "../",
+    "typeRoots": [
+      "../"
+    ],
+    "types": [],
+    "noEmit": true,
+    "forceConsistentCasingInFileNames": true
+  },
+  "files": [
+    "index.d.ts",
+    "react-combine-reducers-tests.ts"
+  ]
+}

types/react-combine-reducers/tslint.json

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+{ "extends": "dtslint/dt.json" }