[playground] Improve DiffEditor scrollbar + view

compiler/apps/playground/components/AccordionWindow.tsx

@@ -7,7 +7,6 @@
 
 import {Resizable} from 're-resizable';
 import React, {
-  useCallback,
   useId,
   unstable_ViewTransition as ViewTransition,
   unstable_addTransitionType as addTransitionType,
@@ -66,7 +65,7 @@ function AccordionWindowItem({
 
   const transitionName = `accordion-window-item-${id}`;
 
-  const toggleTabs = () => {
+  const toggleTabs = (): void => {
     startTransition(() => {
       addTransitionType(EXPAND_ACCORDION_TRANSITION);
       const nextState = new Set(tabsOpen);

compiler/apps/playground/components/Editor/EditorImpl.tsx

@@ -24,11 +24,7 @@ import BabelPluginReactCompiler, {
   printFunctionWithOutlined,
   type LoggerEvent,
 } from 'babel-plugin-react-compiler';
-import {
-  useDeferredValue,
-  useMemo,
-  unstable_ViewTransition as ViewTransition,
-} from 'react';
+import {useDeferredValue, useMemo} from 'react';
 import {useStore} from '../StoreContext';
 import ConfigEditor from './ConfigEditor';
 import Input from './Input';

compiler/apps/playground/components/Editor/Output.tsx

@@ -372,12 +372,18 @@ function TextTabContent({
           loading={''}
           options={{
             ...monacoOptions,
+            scrollbar: {
+              vertical: 'hidden',
+            },
+            dimension: {
+              width: 0,
+              height: 0,
+            },
             readOnly: true,
             lineNumbers: 'off',
             glyphMargin: false,
             // Undocumented see https://github.com/Microsoft/vscode/issues/30795#issuecomment-410998882
-            lineDecorationsWidth: 0,
-            lineNumbersMinChars: 0,
+            overviewRulerLanes: 0,
           }}
         />
       ) : (

compiler/apps/playground/styles/globals.css

@@ -124,3 +124,11 @@
 ::view-transition-group(.expand-accordion) {
   overflow: clip;
 }
+
+/**
+ * For some reason, the original Monaco editor is still visible to the
+ * left of the DiffEditor. This is a workaround for better visual clarity.
+ */
+.monaco-diff-editor .editor.original{
+  visibility: hidden !important;
+}