add eslint

.eslintrc.json

@@ -0,0 +1,28 @@
+{
+    "env": {
+        "es6": true,
+        "node": true
+    },
+    "extends": "eslint:recommended",
+    "parserOptions": {
+        "sourceType": "module"
+    },
+    "rules": {
+        "indent": [
+            "error",
+            4
+        ],
+        "linebreak-style": [
+            "error",
+            "unix"
+        ],
+        "quotes": [
+            "error",
+            "single"
+        ],
+        "semi": [
+            "error",
+            "always"
+        ]
+    }
+}

lib/index.js

@@ -44,7 +44,7 @@ function generateXML(data) {
 
         item_values.push({'turbo:content': {_cdata: fullContent}});
 
-        if (typeof item.related !== "undefined") {
+        if (typeof item.related !== 'undefined') {
             ifTruePush(item.related, item_values, {
                 'yandex:related': item.related.map(
                     function (related) {

package.json

@@ -56,6 +56,7 @@
     "xml": "1.0.1"
   },
   "devDependencies": {
+    "eslint": "^4.19.1",
     "folderify": "^1.1.0",
     "grunt": "^0.4.5",
     "grunt-cli": "^0.1.13",