[Meta PR] Convert to TypeScript

.babelrc.js

@@ -2,6 +2,7 @@ const { NODE_ENV } = process.env
 
 module.exports = {
   presets: [
+    '@babel/typescript',
     [
       '@babel/env',
       {

.eslintignore

@@ -3,3 +3,5 @@
 **/server.js
 **/webpack.config*.js
 **/flow-typed/**
+# TODO: figure out a way to lint this using flow instead of typescript
+examples/todos-flow

.eslintrc.js

@@ -1,22 +1,34 @@
 module.exports = {
   extends: 'react-app',
 
+  parser: '@typescript-eslint/parser',
+
+  plugins: ['@typescript-eslint'],
+
   settings: {
     react: {
       version: '16.8'
+    },
+    'import/parsers': {
+      '@typescript-eslint/parser': ['.ts', '.tsx']
+    },
+    'import/resolver': {
+      // use <root>/tsconfig.json
+      typescript: {}
     }
   },
 
   rules: {
-    'jsx-a11y/href-no-hash': 'off'
-  },
-
-  overrides: [
-    {
-      files: 'test/**/*.js',
-      env: {
-        jest: true,
-      },
-    },
-  ],
+    'jsx-a11y/href-no-hash': 'off',
+    'no-unused-vars': 'off',
+    '@typescript-eslint/no-unused-vars': [
+      'error',
+      {
+        vars: 'all',
+        args: 'after-used',
+        ignoreRestSiblings: true,
+        argsIgnorePattern: '^_' // ignore unused variables whose name is '_'
+      }
+    ]
+  }
 }

examples/todomvc/src/components/App.spec.js

@@ -4,8 +4,7 @@ import App from './App'
 import Header from '../containers/Header'
 import MainSection from '../containers/MainSection'
 
-
-const setup = propOverrides => {
+const setup = _propOverrides => {
   const renderer = createRenderer()
   renderer.render(<App />)
   const output = renderer.getRenderOutput()
@@ -16,16 +15,16 @@ describe('components', () => {
   describe('Header', () => {
     it('should render', () => {
       const output = setup()
-      const [ header ] = output.props.children
+      const [header] = output.props.children
       expect(header.type).toBe(Header)
     })
   })
-  
+
   describe('Mainsection', () => {
     it('should render', () => {
       const output = setup()
-      const [ , mainSection ] = output.props.children
+      const [, mainSection] = output.props.children
       expect(mainSection.type).toBe(MainSection)
     })
   })
-})
+})

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
 }
 
 /**
@@ -326,7 +326,9 @@ export interface Store<S = any, A extends Action = AnyAction> {
    *
    * @param nextReducer The reducer for the store to use instead.
    */
-  replaceReducer(nextReducer: Reducer<S, A>): void
+  replaceReducer<NewState = S, NewActions extends A = A>(
+    nextReducer: Reducer<NewState, NewActions>
+  ): Store<NewState, NewActions>
 
   /**
    * Interoperability point for observable/reactive libraries.
@@ -667,3 +669,9 @@ export function compose<R>(
 ): (...args: any[]) => R
 
 export function compose<R>(...funcs: Function[]): (...args: any[]) => R
+
+export const __DO_NOT_USE__ActionTypes: {
+  INIT: string
+  REPLACE: string
+  PROBE_UNKNOWN_ACTION: () => string
+}