lint-staged

.eslintrc

@@ -0,0 +1,13 @@
+{
+  "parser": "babel-eslint",
+  "parserOptions": {
+    "ecmaVersion": "2018"
+  },
+  "extends": ["eslint:recommended", "eslint-config-prettier"],
+  "rules": {
+    "no-console": "off"
+  },
+  "env": {
+    "browser": true
+  }
+}

.flowconfig

@@ -0,0 +1,11 @@
+[ignore]
+
+[include]
+
+[libs]
+
+[lints]
+
+[options]
+
+[strict]

.lintstagedrc

@@ -0,0 +1,11 @@
+{
+  "linters": {
+    "*.js": [
+      "eslint"
+    ],
+    "*.+(js|jsx|json|yml|yaml|css|less|scss|ts|tsx|md|graphql|mdx)": [
+      "prettier --write",
+      "git add"
+    ]
+  }
+}

.prettierignore

@@ -0,0 +1,7 @@
+node_modules
+coverage
+dist
+build
+.build
+
+# etc...

.prettierrc

@@ -0,0 +1,12 @@
+{
+  "arrowParens": "avoid",
+  "bracketSpacing": false,
+  "jsxBracketSameLine": false,
+  "printWidth": 80,
+  "proseWrap": "always",
+  "semi": false,
+  "singleQuote": true,
+  "tabWidth": 2,
+  "trailingComma": "all",
+  "useTabs": false
+}

package.json

@@ -3,9 +3,24 @@
   "version": "1.0.0",
   "description": "",
   "main": "index.js",
-  "scripts": {},
+  "scripts": {
+    "lint": "eslint src",
+    "flow": "flow",
+    "format": "npm run prettier -- --write",
+    "prettier": "prettier \"**/*.+(js|jsx|json|yml|yaml|css|less|scss|ts|tsx|md|graphql|mdx)\"",
+    "validate": "npm run lint && npm run prettier -- --list-different && npm run flow",
+    "precommit": "lint-staged && npm run flow"
+  },
   "keywords": [],
   "author": "Kent C. Dodds <kent@doddsfamily.us> (http://kentcdodds.com/)",
   "license": "MIT",
-  "devDependencies": {}
+  "devDependencies": {
+    "babel-eslint": "^9.0.0",
+    "eslint": "^5.5.0",
+    "eslint-config-prettier": "^3.0.1",
+    "flow-bin": "^0.81.0",
+    "husky": "^0.14.3",
+    "lint-staged": "^7.2.2",
+    "prettier": "^1.14.2"
+  }
 }

src/example.js

@@ -1,11 +1,10 @@
 const name = 'Freddy'
-typeof name === 'strng'
+typeof name === 'string'
 
-if (!'serviceWorker' in navigator) {
+if (!('serviceWorker' in navigator)) {
   // you have an old browser :-(
 }
 
 const greeting = 'hello'
-console.log('${greting} world!')
+console.log(`${greeting} world!`)
-
+;[(1, 2, 3)].forEach(x => console.log(x))
-[(1, 2, 3)].forEach(x => console.log(x))

src/flow-example.js

@@ -0,0 +1,22 @@
+// @flow
+function add(a: number, b: number): number {
+  return a + b
+}
+
+type User = {
+  name: {
+    first: string,
+    middle: string,
+    last: string,
+  },
+}
+function getFullName(user: User): string {
+  const {
+    name: {first, middle, last},
+  } = user
+  return [first, middle, last].filter(Boolean).join('')
+}
+
+add(1, 2)
+
+getFullName({name: {first: 'Joe', middle: 'Bud', last: 'Matthews'}})