Configure CoffeeScript compilation with Webpacker

config/webpack/environment.js

@@ -1,3 +1,5 @@
 const { environment } = require('@rails/webpacker')
+const coffee =  require('./loaders/coffee')
 
+environment.loaders.prepend('coffee', coffee)
 module.exports = environment

config/webpack/loaders/coffee.js

@@ -0,0 +1,12 @@
+module.exports = {
+  test: /\.coffee(\.erb)?$/,
+  use: [{
+    loader: 'coffee-loader',
+    options: {
+      bare: false,
+      transpile: {
+        presets: ['@babel/preset-env'],
+      },
+    }
+  }]
+}

config/webpacker.yml

@@ -10,7 +10,7 @@ default: &default
 
   # Additional paths webpack should lookup modules
   # ['app/assets', 'engine/foo/app/assets']
-  additional_paths: []
+  resolved_paths: []
 
   # Reload manifest.json on all requests so we reload latest compiled packs
   cache_manifest: false
@@ -33,6 +33,7 @@ default: &default
     - .woff2
 
   extensions:
+    - .coffee
     - .mjs
     - .js
     - .sass
@@ -89,4 +90,4 @@ production:
   extract_css: true
 
   # Cache manifest.json for performance
-  cache_manifest: true
+  cache_manifest: true