Code style

.editorconfig

@@ -0,0 +1,9 @@
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+trim_trailing_whitespace = true
+insert_final_newline = true
+indent_style = space
+indent_size = 2

.eslintrc.json

@@ -0,0 +1,30 @@
+{
+    "env": {
+        "browser": true,
+        "es6": true,
+        "node": true
+    },
+    "extends": "eslint:recommended",
+    "parserOptions": {
+        "ecmaVersion": 2016,
+        "sourceType": "module"
+    },
+    "rules": {
+        "indent": [
+            "error",
+            4
+        ],
+        "linebreak-style": [
+            "error",
+            "unix"
+        ],
+        "quotes": [
+            "error",
+            "single"
+        ],
+        "semi": [
+            "error",
+            "always"
+        ]
+    }
+}

.travis.yml

@@ -5,6 +5,7 @@ install:
 node_js:
   - "7"
 script:
+  - npm run lint
   - npm run build
   - npm run test
-  - codecov
+  - codecov

package.json

@@ -8,7 +8,8 @@
     "build": "rollup -c",
     "watch": "rollup -c -w",
     "watch:test": "npm-watch test",
-    "prepublish": "rollup -c"
+    "prepublish": "rollup -c",
+    "lint": "eslint engine/**"
   },
   "watch": {
     "test": {
@@ -27,6 +28,7 @@
     "babel-plugin-external-helpers": "6.22.0",
     "babel-plugin-transform-object-assign": "6.22.0",
     "babel-preset-env": "1.7.0",
+    "eslint": "^5.0.1",
     "istanbul": "0.4.5",
     "jasmine": "3.1.0",
     "npm-watch": "0.3.0",