fix(webpack-cli): prefetch flag implementation

packages/webpack-cli/__tests__/AdvancedGroup.test.js

@@ -0,0 +1,25 @@
+const AdvancedGroup = require('../lib/groups/AdvancedGroup');
+
+describe('AdvancedGroup', function () {
+    it('should load the HMR Plugin', () => {
+        const group = new AdvancedGroup([
+            {
+                hot: true,
+            },
+        ]);
+
+        const result = group.run();
+        expect(result.options.plugins[0].constructor.name).toEqual('HotModuleReplacementPlugin');
+    });
+
+    it('should load the Prefetch Plugin', () => {
+        const group = new AdvancedGroup([
+            {
+                prefetch: 'url',
+            },
+        ]);
+
+        const result = group.run();
+        expect(result.options.plugins[0].constructor.name).toEqual('PrefetchPlugin');
+    });
+});

packages/webpack-cli/lib/groups/AdvancedGroup.js

@@ -25,8 +25,7 @@ class AdvancedGroup extends GroupHelper {
             if (options && options.plugins) {
                 options.plugins.unshift(prefetchVal);
             } else {
-                // Currently the Plugin function is not functional  -> https://github.com/webpack/webpack-cli/pull/1140#discussion_r376761359
-                // options.plugins = [prefetchVal];
+                options.plugins = [prefetchVal];
             }
         }
         if (args.target) {