diff --git a/src/operations/category-chart.component.ts b/src/operations/category-chart.component.ts
index 7fc1e64..c9f5fcd 100644
--- a/src/operations/category-chart.component.ts
+++ b/src/operations/category-chart.component.ts
@@ -18,10 +18,10 @@
 /* jshint node: true */
 'use strict';
 
-var moment = require('moment'),
-    c3     = require('c3');
+import * as moment from 'moment';
+import * as c3 from 'c3';
 
-var angular = require('angular');
+import * as angular from 'angular';
 
 var ngResource = require('angular-resource');