Lint code examples (#1171)

* feat: lint configuration

* style: linted documentation

* fix: missing dep

.eslintrc

@@ -0,0 +1,13 @@
+{
+  "extends": "babel",
+  "rules": {
+    "no-unused-vars": 1
+  },
+  "plugins": [
+    "markdown"
+  ],
+  "env": {
+    "node": true,
+    "mocha": true
+  }
+}

.travis.yml

@@ -12,7 +12,7 @@ before_install:
   - git submodule update --init --recursive
 
 script:
-  - npm test && bundle exec rake
+  - npm test && npm run lint && bundle exec rake
 
 git:
   submodules: false

docs/faq.md

@@ -21,7 +21,7 @@ Arrow functions **are not** synonymous with normal functions. `arguments` and `t
 reference their *outer function* for example:
 
 ```javascript
-var user = {
+const user = {
   firstName: "Sebastian",
   lastName: "McKenzie",
   getFullName: () => {

docs/plugins.md

@@ -338,13 +338,13 @@ to learn how to create your own plugins.
 The simple plugin that reverses names (from the homepage):
 
 ```js
-export default function ({types: t}) {
+export default function ({ types: t }) {
   return {
     visitor: {
       Identifier(path) {
-        let name = path.node.name;
+        const name = path.node.name;
         // reverse the name: JavaScript -> tpircSavaJ
-        path.node.name = name.split('').reverse().join('');
+        path.node.name = name.split("").reverse().join("");
       }
     }
   };
@@ -359,11 +359,11 @@ To make your own preset, you just need to export a config.
 // Presets can contain other presets, and plugins with options.
 module.exports = {
   presets: [
-    require('babel-preset-es2015'),
+    require("babel-preset-es2015"),
   ],
   plugins: [
-    [require('babel-plugin-transform-es2015-template-literals'), { spec: true }],
-    require('babel-plugin-transform-es3-member-expression-literals'),
+    [require("babel-plugin-transform-es2015-template-literals"), { spec: true }],
+    require("babel-plugin-transform-es3-member-expression-literals"),
   ],
 };
 ```

docs/usage/polyfill.md

@@ -52,7 +52,7 @@ With `webpack.config.js`, add `babel-polyfill` to your entry array:
 
 ```js
 module.exports = {
-   entry: ['babel-polyfill', './app/js']
+  entry: ["babel-polyfill", "./app/js"]
 };
 ```
 

package.json

@@ -7,6 +7,7 @@
   "scripts": {
     "start": "make serve",
     "build": "make build",
+    "lint": "eslint --ext md docs",
     "test": "remark _posts docs _includes README.md --quiet"
   },
   "remarkConfig": {
@@ -30,7 +31,12 @@
   "author": "",
   "license": "ISC",
   "devDependencies": {
+    "babel-eslint": "^7.1.1",
     "bootstrap-sass": "^3.3.1",
+    "eslint": "^3.15.0",
+    "eslint-config-babel": "^6.0.0",
+    "eslint-plugin-flowtype": "^2.30.0",
+    "eslint-plugin-markdown": "^1.0.0-beta.3",
     "remark-cli": "^2.1.0",
     "remark-lint": "^5.2.0",
     "remark-preset-lint-recommended": "^1.0.0"