diff --git a/packages/learn/src/templates/Challenges/views/classic/Editor.js b/packages/learn/src/templates/Challenges/views/classic/Editor.js
index 06459b7b42..86de58fccd 100644
--- a/packages/learn/src/templates/Challenges/views/classic/Editor.js
+++ b/packages/learn/src/templates/Challenges/views/classic/Editor.js
@@ -9,8 +9,10 @@ import { executeChallenge, updateFile } from '../../redux';
 import 'codemirror/lib/codemirror.css';
 import 'codemirror/theme/material.css';
 
-require('codemirror/mode/htmlmixed/htmlmixed');
-require('codemirror/mode/javascript/javascript');
+if (typeof window !== 'undefined') {
+  require('codemirror/mode/htmlmixed/htmlmixed');
+  require('codemirror/mode/javascript/javascript');
+}
 
 const propTypes = {
   contents: PropTypes.string,