install and run prettier

.eslintrc

@@ -6,13 +6,9 @@
       "jsx": true
     }
   },
+  "extends": ["eslint:recommended"],
   "rules": {
-    "strict": ["error", "never"],
-    "valid-typeof": "error",
-    "no-unsafe-negation": "error",
-    "no-unused-vars": "error",
-    "no-unexpected-multiline": "error",
-    "no-undef": "error"
+    "strict": ["error", "never"]
   },
   "env": {
     "browser": true

package-lock.json

@@ -3178,6 +3178,12 @@
       "integrity": "sha1-IZMqVJ9eUv/ZqCf1cOBL5iqX2lQ=",
       "dev": true
     },
+    "prettier": {
+      "version": "1.19.1",
+      "resolved": "https://registry.npmjs.org/prettier/-/prettier-1.19.1.tgz",
+      "integrity": "sha512-s7PoyDv/II1ObgQunCbB9PdLmUcBZcnWOcxDh7O0N/UwDEsHyqkW+Qh28jW+mVuCdx7gLB0BotYI1Y6uI9iyew==",
+      "dev": true
+    },
     "private": {
       "version": "0.1.8",
       "resolved": "https://registry.npmjs.org/private/-/private-0.1.8.tgz",

package.json

@@ -4,12 +4,15 @@
   "author": "Kent C. Dodds (http://kentcdodds.com/)",
   "license": "GPLv3",
   "scripts": {
-    "build": "babel src --out-dir dist"
+    "build": "babel src --out-dir dist",
+    "lint": "eslint --ignore-path .gitignore .",
+    "format": "prettier --ignore-path .gitignore --write \"**/*.+(js|json)\""
   },
   "devDependencies": {
     "@babel/cli": "^7.7.0",
     "@babel/core": "^7.7.2",
     "@babel/preset-env": "^7.7.1",
-    "eslint": "^6.6.0"
+    "eslint": "^6.6.0",
+    "prettier": "^1.19.1"
   }
 }

src/example.js

@@ -1,12 +1,10 @@
-'use strict'
+const username = "freddy";
+typeof username === "string";
 
-const username = 'freddy'
-typeof username === 'strng'
-
-if (!'serviceWorker' in navigator) {
+if (!("serviceWorker" in navigator)) {
   // you have an old browser :-(
 }
 
-const greeting = 'hello'
-console.log('${greeting} world!')
-[1, 2, 3].forEach(x => console.log(x))
+const greeting = "hello";
+console.log(`${greeting} world!`);
+[1, 2, 3].forEach(x => console.log(x));