use const instead var in node.js v6 above

app.js

@@ -1,15 +1,16 @@
-var express = require('express'),
-    path = require('path'),
-    favicon = require('serve-favicon'),
-    logger = require('morgan'),
-    cookieParser = require('cookie-parser'),
-    bodyParser = require('body-parser'),
-    config = require('./config'),
-    i18n = require("i18n");
+const express = require('express');
+const path = require('path');
+const favicon = require('serve-favicon');
+const logger = require('morgan');
+const cookieParser = require('cookie-parser');
+const bodyParser = require('body-parser');
+const i18n = require("i18n");
 
-var routes = require('./routes/index');
+const config = require('./config');
 
-var app = express();
+const routes = require('./routes/index');
+
+const app = express();
 
 i18n.configure({
     defaultLocale: "en",
@@ -38,7 +39,7 @@ app.use('/', routes);
 
 // catch 404 and forward to error handler
 app.use(function(req, res, next) {
-    var err = new Error('Not Found');
+    const err = new Error('Not Found');
     err.status = 404;
     next(err);
 });

bin/www

@@ -1,9 +1,9 @@
 #!/usr/bin/env node
 
 // support for .env file to get loaded in to environment variables.
-var path = require('path');
-var fs = require('fs');
-var envFile = path.join(__dirname, '../.env');
+const path = require('path');
+const fs = require('fs');
+const envFile = path.join(__dirname, '../.env');
 try {
   fs.accessSync(envFile, fs.F_OK);
   require('dotenv').config({path: envFile});
@@ -14,16 +14,16 @@ try {
 /**
 * Module dependencies.
 */
-var app = require('../app');
-var debug = require('debug')('slack-invite-automation:server');
-var http = require('http');
+const app = require('../app');
+const debug = require('debug')('slack-invite-automation:server');
+const http = require('http');
 
 /**
  * Normalize a port into a number, string, or false.
  * @param {int} val
  */
 function normalizePort(val) {
-    var port = parseInt(val, 10);
+    const port = parseInt(val, 10);
     if (isNaN(port)) {
         return val;
     } else if (port >= 0) {
@@ -38,14 +38,14 @@ function normalizePort(val) {
  * Get port from environment and store in Express.
  */
 
-var port = normalizePort(process.env.PORT || '3000');
+const port = normalizePort(process.env.PORT || '3000');
 app.set('port', port);
 
 /**
  * Create HTTP server.
  */
 
-var server = http.createServer(app);
+const server = http.createServer(app);
 
 /**
  * Listen on provided port, on all network interfaces.

routes/index.js

@@ -1,7 +1,7 @@
-var express = require('express');
-var router = express.Router();
-var request = require('request');
-var config = require('../config');
+const express = require('express');
+const router = express.Router();
+const request = require('request');
+const config = require('../config');
 
 router.get('/', function(req, res) {
   res.setLocale(config.locale);
@@ -33,7 +33,7 @@ router.post('/invite', function(req, res) {
               message: 'Success! Check “'+ req.body.email +'” for an invite from Slack.'
             });
           } else {
-            var error = body.error;
+            const error = body.error;
             if (error === 'already_invited' || error === 'already_in_team') {
               res.render('result', {
                 community: config.community,
@@ -82,7 +82,7 @@ router.post('/invite', function(req, res) {
       doInvite();
     }
   } else {
-    var errMsg = [];
+    const errMsg = [];
     if (!req.body.email) {
       errMsg.push('your email is required');
     }