diff --git a/lib/appenders/slack.js b/lib/appenders/slack.js
index e1af222..cb32665 100644
--- a/lib/appenders/slack.js
+++ b/lib/appenders/slack.js
@@ -1,38 +1,37 @@
-"use strict";
-var Slack = require('slack-node');
-var layouts = require('../layouts');
-var layout;
+'use strict';
 
-var slack, config;
+const Slack = require('slack-node');
+const layouts = require('../layouts');
+let layout;
+
+let slack;
 
 function slackAppender(_config, _layout) {
-
   layout = _layout || layouts.basicLayout;
 
-  return function (loggingEvent) {
-
-    var data = {
+  return loggingEvent => {
+    const data = {
       channel_id: _config.channel_id,
       text: layout(loggingEvent, _config.timezoneOffset),
       icon_url: _config.icon_url,
       username: _config.username
     };
 
+    /* eslint no-unused-vars:0 */
     slack.api('chat.postMessage', {
       channel: data.channel_id,
       text: data.text,
-      icon_url: data.icon_url, username: data.username
-    }, function (err, response) {
+      icon_url: data.icon_url,
+      username: data.username
+    }, (err, response) => {
       if (err) {
         throw err;
       }
     });
-
   };
 }
 
 function configure(_config) {
-
   if (_config.layout) {
     layout = layouts.layout(_config.layout.type, _config.layout);
   }
@@ -42,6 +41,6 @@ function configure(_config) {
   return slackAppender(_config, layout);
 }
 
-exports.name = 'slack';
-exports.appender = slackAppender;
-exports.configure = configure;
+module.exports.name = 'slack';
+module.exports.appender = slackAppender;
+module.exports.configure = configure;