Prettier fixes

lib/util/extend.js

@@ -1,21 +1,21 @@
 module.exports = function(target) {
   if (target == null) {
-    return null
+    return null;
   }
 
-  var to = Object(target)
+  var to = Object(target);
 
   for (var i = 1; i < arguments.length; i++) {
-    var source = arguments[i]
+    var source = arguments[i];
 
     if (source != null) {
       for (var key in source) {
         // Avoid bugs when hasOwnProperty is shadowed
         if (Object.prototype.hasOwnProperty.call(source, key)) {
-          to[key] = source[key]
+          to[key] = source[key];
         }
       }
     }
   }
-  return to
-}
+  return to;
+};