diff --git a/lib/cartodb/models/dataview/histogram.js b/lib/cartodb/models/dataview/histogram.js
index 25a08da0..5a4f713b 100644
--- a/lib/cartodb/models/dataview/histogram.js
+++ b/lib/cartodb/models/dataview/histogram.js
@@ -1,6 +1,6 @@
-var _ = require('underscore');
-var BaseWidget = require('./base');
-var debug = require('debug')('windshaft:dataview:histogram');
+const _ = require('underscore');
+const BaseWidget = require('./base');
+const debug = require('debug')('windshaft:dataview:histogram');
 
 const columnCastTpl = ctx => `date_part('epoch', ${ctx.column})`;