fix(stimulus): don't require an optional dependency if it's not used

Author: Kocal

lib/features.js

@@ -147,6 +147,14 @@ const features = {
             { name: 'handlebars-loader', enforce_version: true }
         ],
         description: 'load Handlebars files'
+    },
+    stimulus: {
+        method: 'enableStimulusBridge()',
+        packages: [
+            { name: '@symfony/stimulus-bridge' },
+            { name: 'stimulus' }
+        ],
+        description: 'enable Stimulus bridge'
     }
 };
 

lib/plugins/stimulus-bridge.js

@@ -10,7 +10,7 @@
 'use strict';
 
 const WebpackConfig = require('../WebpackConfig'); //eslint-disable-line no-unused-vars
-const createPlugin = require('@symfony/stimulus-bridge/webpack-helper');
+const loaderFeatures = require('../features');
 const fs = require('fs');
 
 /**
@@ -20,6 +20,10 @@ const fs = require('fs');
  */
 module.exports = function(plugins, webpackConfig) {
     if (webpackConfig.useStimulusBridge) {
+        loaderFeatures.ensurePackagesExistAndAreCorrectVersion('stimulus');
+
+        const createPlugin = require('@symfony/stimulus-bridge/webpack-helper');
+
         plugins.push({
             plugin: createPlugin(JSON.parse(fs.readFileSync(webpackConfig.stimulusOptions.controllersJsonPath))),
         });