Add prettier

This also sets up ESLint to get tighter tooling feedback for people who
aren't me and don't have format-on-save.

Author: zpao

Diff for: .eslintrc.js

@@ -0,0 +1,7 @@
+module.exports = {
+  parserOptions: {ecmaVersion: 6},
+  plugins: ['prettier'],
+  rules: {
+    'prettier/prettier': 'error',
+  },
+};

Diff for: package.json

@@ -9,6 +9,9 @@
   ],
   "main": "index.js",
   "scripts": {
+    "lint": "eslint .",
+    "format":
+      "prettier --write *.js package.json .eslintrc.js 'examples/**/*.{js,json}' 'test/*.{js,jsx,json}'",
     "test": "node test"
   },
   "author": "Paul O’Shannessy <[email protected]>",
@@ -32,6 +35,9 @@
   "devDependencies": {
     "async": "^2.4.0",
     "create-react-class": "^15.5.3",
+    "eslint": "^4.10.0",
+    "eslint-plugin-prettier": "^2.3.1",
+    "prettier": "^1.7.4",
     "prop-types": "^15.5.10",
     "react": "^16.0.0",
     "react-dom": "^16.0.0"

Diff for: prettier.config.js

@@ -0,0 +1,8 @@
+module.exports = {
+  printWidth: 80,
+  semi: true,
+  bracketSpacing: false,
+  jsxBracketSameLine: true,
+  singleQuote: true,
+  trailingComma: 'es5',
+};