dgrochowski · dgrochowski · Mar 16, 2018
diff --git a/README.md b/README.md
@@ -38,6 +38,7 @@ Deployment to [Github pages](https://dgrochowski.github.io/frontend-upskilling/)
 - In ES6 you can marked `var` as deprecated
   - To declare objects and arrays you should use `const` (as often as possible)
   - If you cannot use `const`, use `let`
+- `'use strict;'` mode will force you to create better quality code. Use it as often as you can.
 
 # Webpack
 

diff --git a/docs/index.html b/docs/index.html
@@ -46,6 +46,7 @@ <h3>JavaScript</h3>
         <li><a href="javascript/17-cookies-storage.html">Cookies, local storage, session storage</a></li>
         <li><a href="javascript/18-async.html">Async: timeout, interval, XMLHttpRequest (xhr), ajax, fetch</a></li>
         <li><a href="javascript/19-regular-expressions.html">Regular expressions</a></li>
+        <li><a href="javascript/20-es6-module-system.html">ES6 - Module system</a></li>
         <li><a href="javascript/21-es6-let-const.html">ES6 - let, const</a></li>
     </ul>
 </body>

diff --git a/docs/javascript/20-es6-module-system.html b/docs/javascript/20-es6-module-system.html
@@ -0,0 +1,15 @@
+<!DOCTYPE html>
+<html>
+<head>
+    <meta charset="utf-8" />
+    <title>JavaScript - ES6 Module system</title>
+    <!--<script type="module" src="_include/21-export.js"></script>-->
+    <script>
+        import a from '_include/21-export';
+        // console.log (a);
+    </script>
+</head>
+<body>
+    <h3>Check console (right click -> inspect -> console)</h3>
+</body>
+</html>
diff --git a/docs/javascript/_include/21-export.js b/docs/javascript/_include/21-export.js
@@ -0,0 +1,18 @@
+// function myFunction() {
+//     return 'something new here';
+// }
+//
+// // exports a function declared earlier
+// export { myFunction };
+//
+// // exports a constant
+// export const foo = 'some constant var';
+//
+// // default export function
+// export default function() {}
+//
+// // default export class
+// export default class {}
+
+// default export variable
+// export default a = 'default var';