fix for undefined, back to production mode

src/js/index.js

@@ -134,6 +134,7 @@ const handle_enter = function () {
                 let tokens = scan(command);
                 let statement = parse(tokens);
                 value = visit(statement);
+                if (value !== undefined) {
                     let binding;
                     if (value.is_binding) {                         // if it's declaration work with the initializer
                         binding = value.name;                       // but we also need the name of the bound variable
@@ -167,6 +168,9 @@ const handle_enter = function () {
                     if (value.description) {
                         value = value.description;
                     }
+                } else {
+                    value = 'value is undefined';
+                }
             } catch (exception) {
                 value = exception.message;
             }

webpack.config.js

@@ -2,7 +2,7 @@ const path = require('path');
 const HtmlWebpackPlugin = require("html-webpack-plugin");
 
 module.exports = {
-    mode: 'development',
+    mode: 'production',
     entry: './src/js/index.js',
 
     output: {