diff --git a/lib/appenders/categoryFilter.js b/lib/appenders/categoryFilter.js
index 2a369b9..26fc2b9 100644
--- a/lib/appenders/categoryFilter.js
+++ b/lib/appenders/categoryFilter.js
@@ -1,9 +1,10 @@
-"use strict";
-var log4js = require('../log4js');
+'use strict';
+
+const log4js = require('../log4js');
 
 function categoryFilter(excludes, appender) {
   if (typeof(excludes) === 'string') excludes = [excludes];
-  return function (logEvent) {
+  return logEvent => {
     if (excludes.indexOf(logEvent.categoryName) === -1) {
       appender(logEvent);
     }
@@ -12,9 +13,9 @@ function categoryFilter(excludes, appender) {
 
 function configure(config, options) {
   log4js.loadAppender(config.appender.type);
-  var appender = log4js.appenderMakers[config.appender.type](config.appender, options);
+  const appender = log4js.appenderMakers[config.appender.type](config.appender, options);
   return categoryFilter(config.exclude, appender);
 }
 
-exports.appender = categoryFilter;
-exports.configure = configure;
+module.exports.appender = categoryFilter;
+module.exports.configure = configure;