scaffolding for typescript (#3504)

* scaffolding for typescript

* add jest types so tests will compile

* remove rollup-plugin-typescript2, probably don't need it

* add missing eslint-import

* fix linting errors

.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 +1,43 @@
 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'
+    '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 '_'
+      }
+    ]
   },
 
   overrides: [
     {
       files: 'test/**/*.js',
       env: {
-        jest: true,
-      },
-    },
-  ],
+        jest: true
+      }
+    }
+  ]
 }

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)
     })
   })
-})
+})