rename to google-datastore, and use Date.now()

lib/document_stores/google-datastore.js

@@ -14,8 +14,7 @@ class GoogleDatastoreDocumentStore {
 
   // Save file in a key
   set(key, data, callback, skipExpire) {
-    var now = new Date();
-    var expireTime = (skipExpire || this.expire === undefined) ? null : new Date(now.getTime() + this.expire * 1000);
+    var expireTime = (skipExpire || this.expire === undefined) ? null : new Date(Date.now() + this.expire * 1000);
     
     var taskKey = this.datastore.key([this.kind, key])
     var task = {
@@ -59,7 +58,6 @@ class GoogleDatastoreDocumentStore {
         else {
         
           // update expiry
-          var now = new Date();
           var task = {
             key: taskKey,
             data: [
@@ -70,7 +68,7 @@ class GoogleDatastoreDocumentStore {
               },
               {
                 name: 'expiration',
-                value: new Date(now.getTime() + this.expire * 1000)
+                value: new Date(Date.now() + this.expire * 1000)
               }
             ]
           };