Fix linting errors

webpack.config.js

-/*global path, __dirname, module */
+/*global path, __dirname, module, process */
 'use strict'
 const minimist = require('minimist');
 const path = require('path');
@@ -120,17 +120,13 @@ const config = {
     }
 }
 
-function getCLIArgument (name) {
-    return value;
-}
-
 function extend (o1, o2) {
-	for (let i in o2) {
-		if (o2.hasOwnProperty(i)) {
+    for (var i in o2) {
+        if (Object.prototype.hasOwnProperty.call(o2, i)) {
             o1[i] = o2[i];
         }
     }
-};
+}
 
 function parameterize () {
     const type = minimist(process.argv.slice(2)).type;
@@ -175,7 +171,7 @@ function parameterize () {
 
     if (mode === 'production') {
         console.log("Making a production build");
-        let fn = config.output.filename;
+        const fn = config.output.filename;
         config.output.filename = `${fn.replace(/\.js$/, '')}.min.js`;
     }