[DevTools] Add a Code Editor Sidebar Pane in the Chrome Sources Tab (facebook#33968)

This adds a "Code Editor" pane for the Chrome extension in the bottom
right corner of the "Sources" panel. If you end up getting linked to the
"Sources" panel from stack traces in console, performance tab, stacks in
React Component tab like the one added in facebook#33954 basically everywhere
there's a link to source code. Then going from there to open in a code
editor should be more convenient. This adds a button to open the current
file.

<img width="1387" height="389" alt="Screenshot 2025-07-22 at 10 22
19 PM"
src="https://github.com/user-attachments/assets/fe01f84c-83c2-4639-9b64-4af1a90c3f7d"
/>

This only makes sense in the extensions since in standalone it needs to
always open by default in an editor. Unfortunately Firefox doesn't
support extending the Sources panel.

Chrome is also a bit buggy where it doesn't send a selection update
event when you switch tabs in the Sources panel. Only when the actual
cursor position changes. This means that the link can be lagging behind
sometimes. We also have some general bugs where if React DevTools loses
connection it can break the UI which includes this pane too.

This has a small inline configuration too so that it's discoverable:

<img width="559" height="143" alt="Screenshot 2025-07-22 at 10 22 42 PM"
src="https://github.com/user-attachments/assets/1270bda8-ce10-4f9d-9fcb-080c0198366a"
/>

<img width="527" height="123" alt="Screenshot 2025-07-22 at 10 22 30 PM"
src="https://github.com/user-attachments/assets/45848c95-afd8-495f-a7cf-eb2f46e698f2"
/>

Since we can't add a separate link to open-in-editor or open-in-sources
everywhere I plan on adding an option to open in editor by default in a
follow up. That option needs to be even more discoverable.

I moved the configuration from the Components settings to the General
settings since this is now a much more general features for opening
links to resources in all types of panes.

<img width="673" height="311" alt="Screenshot 2025-07-22 at 10 22 57 PM"
src="https://github.com/user-attachments/assets/ea2c0871-942c-4b55-a362-025835d2c2bd"
/>

Author: sebmarkbage

packages/react-devtools-extensions/src/main/index.js

@@ -1,5 +1,7 @@
 /* global chrome */
 
+import type {SourceSelection} from 'react-devtools-shared/src/devtools/views/Editor/EditorPane';
+
 import {createElement} from 'react';
 import {flushSync} from 'react-dom';
 import {createRoot} from 'react-dom/client';
@@ -73,19 +75,60 @@ function createBridge() {
     );
   });
 
+  const sourcesPanel = chrome.devtools.panels.sources;
+
   const onBrowserElementSelectionChanged = () =>
     setReactSelectionFromBrowser(bridge);
+  const onBrowserSourceSelectionChanged = (___location: {
+    url: string,
+    startLine: number,
+    startColumn: number,
+    endLine: number,
+    endColumn: number,
+  }) => {
+    if (
+      currentSelectedSource === null ||
+      currentSelectedSource.url !== ___location.url
+    ) {
+      currentSelectedSource = {
+        url: ___location.url,
+        selectionRef: {
+          // We use 1-based line and column, Chrome provides them 0-based.
+          line: ___location.startLine + 1,
+          column: ___location.startColumn + 1,
+        },
+      };
+      // Rerender with the new file selection.
+      render();
+    } else {
+      // Update the ref to the latest position without updating the url. No need to rerender.
+      const selectionRef = currentSelectedSource.selectionRef;
+      selectionRef.line = ___location.startLine + 1;
+      selectionRef.column = ___location.startColumn + 1;
+    }
+  };
   const onBridgeShutdown = () => {
     chrome.devtools.panels.elements.onSelectionChanged.removeListener(
       onBrowserElementSelectionChanged,
     );
+    if (sourcesPanel) {
+      currentSelectedSource = null;
+      sourcesPanel.onSelectionChanged.removeListener(
+        onBrowserSourceSelectionChanged,
+      );
+    }
   };
 
   bridge.addListener('shutdown', onBridgeShutdown);
 
   chrome.devtools.panels.elements.onSelectionChanged.addListener(
     onBrowserElementSelectionChanged,
   );
+  if (sourcesPanel) {
+    sourcesPanel.onSelectionChanged.addListener(
+      onBrowserSourceSelectionChanged,
+    );
+  }
 }
 
 function createBridgeAndStore() {
@@ -152,11 +195,13 @@ function createBridgeAndStore() {
         bridge,
         browserTheme: getBrowserTheme(),
         componentsPortalContainer,
+        profilerPortalContainer,
+        editorPortalContainer,
+        currentSelectedSource,
         enabledInspectedElementContextMenu: true,
         fetchFileWithCaching,
         hookNamesModuleLoaderFunction,
         overrideTab,
-        profilerPortalContainer,
         showTabBar: false,
         store,
         warnIfUnsupportedVersionDetected: true,
@@ -257,6 +302,53 @@ function createProfilerPanel() {
   );
 }
 
+function createSourcesEditorPanel() {
+  if (editorPortalContainer) {
+    // Panel is created and user opened it at least once
+    ensureInitialHTMLIsCleared(editorPortalContainer);
+    render();
+
+    return;
+  }
+
+  if (editorPane) {
+    // Panel is created, but wasn't opened yet, so no document is present for it
+    return;
+  }
+
+  const sourcesPanel = chrome.devtools.panels.sources;
+  if (!sourcesPanel) {
+    // Firefox doesn't currently support extending the source panel.
+    return;
+  }
+
+  sourcesPanel.createSidebarPane('Code Editor ⚛', createdPane => {
+    editorPane = createdPane;
+
+    createdPane.setPage('panel.html');
+    createdPane.setHeight('42px');
+
+    createdPane.onShown.addListener(portal => {
+      editorPortalContainer = portal.container;
+      if (editorPortalContainer != null && render) {
+        ensureInitialHTMLIsCleared(editorPortalContainer);
+
+        render();
+        portal.injectStyles(cloneStyleTags);
+
+        logEvent({event_name: 'selected-editor-pane'});
+      }
+    });
+
+    createdPane.onShown.addListener(() => {
+      bridge.emit('extensionEditorPaneShown');
+    });
+    createdPane.onHidden.addListener(() => {
+      bridge.emit('extensionEditorPaneHidden');
+    });
+  });
+}
+
 function performInTabNavigationCleanup() {
   // Potentially, if react hasn't loaded yet and user performs in-tab navigation
   clearReactPollingInstance();
@@ -356,6 +448,7 @@ function mountReactDevTools() {
 
   createComponentsPanel();
   createProfilerPanel();
+  createSourcesEditorPanel();
 }
 
 let reactPollingInstance = null;
@@ -394,13 +487,17 @@ let profilingData = null;
 
 let componentsPanel = null;
 let profilerPanel = null;
+let editorPane = null;
 let componentsPortalContainer = null;
 let profilerPortalContainer = null;
+let editorPortalContainer = null;
 
 let mostRecentOverrideTab = null;
 let render = null;
 let root = null;
 
+let currentSelectedSource: null | SourceSelection = null;
+
 let port = null;
 
 // In case when multiple navigation events emitted in a short period of time

packages/react-devtools-shared/src/devtools/views/ButtonLabel.css

@@ -0,0 +1,7 @@
+.ButtonLabel {
+  padding-left: 1.5rem;
+  margin-left: -1rem;
+  user-select: none;
+  flex: 1 0 auto;
+  text-align: center;
+}

packages/react-devtools-shared/src/devtools/views/ButtonLabel.js

@@ -0,0 +1,20 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+
+import * as React from 'react';
+
+import styles from './ButtonLabel.css';
+
+type Props = {
+  children: React$Node,
+};
+
+export default function ButtonLabel({children}: Props): React.Node {
+  return <span className={styles.ButtonLabel}>{children}</span>;
+}

packages/react-devtools-shared/src/devtools/views/Components/OpenInEditorButton.js

@@ -14,64 +14,14 @@ import ButtonIcon from 'react-devtools-shared/src/devtools/views/ButtonIcon';
 
 import type {ReactFunctionLocation} from 'shared/ReactTypes';
 
+import {checkConditions} from '../Editor/utils';
+
 type Props = {
   editorURL: string,
   source: ReactFunctionLocation,
   symbolicatedSourcePromise: Promise<ReactFunctionLocation | null>,
 };
 
-function checkConditions(
-  editorURL: string,
-  source: ReactFunctionLocation,
-): {url: URL | null, shouldDisableButton: boolean} {
-  try {
-    const url = new URL(editorURL);
-
-    const [, sourceURL, line] = source;
-    let filePath;
-
-    // Check if sourceURL is a correct URL, which has a protocol specified
-    if (sourceURL.startsWith('file:///')) {
-      filePath = new URL(sourceURL).pathname;
-    } else if (sourceURL.includes('://')) {
-      // $FlowFixMe[cannot-resolve-name]
-      if (!__IS_INTERNAL_VERSION__) {
-        // In this case, we can't really determine the path to a file, disable a button
-        return {url: null, shouldDisableButton: true};
-      } else {
-        const endOfSourceMapURLPattern = '.js/';
-        const endOfSourceMapURLIndex = sourceURL.lastIndexOf(
-          endOfSourceMapURLPattern,
-        );
-
-        if (endOfSourceMapURLIndex === -1) {
-          return {url: null, shouldDisableButton: true};
-        } else {
-          filePath = sourceURL.slice(
-            endOfSourceMapURLIndex + endOfSourceMapURLPattern.length,
-            sourceURL.length,
-          );
-        }
-      }
-    } else {
-      filePath = sourceURL;
-    }
-
-    const lineNumberAsString = String(line);
-
-    url.href = url.href
-      .replace('{path}', filePath)
-      .replace('{line}', lineNumberAsString)
-      .replace('%7Bpath%7D', filePath)
-      .replace('%7Bline%7D', lineNumberAsString);
-
-    return {url, shouldDisableButton: false};
-  } catch (e) {
-    // User has provided incorrect editor url
-    return {url: null, shouldDisableButton: true};
-  }
-}
-
 function OpenInEditorButton({
   editorURL,
   source,

packages/react-devtools-shared/src/devtools/views/DevTools.js

@@ -24,6 +24,7 @@ import {
 import Components from './Components/Components';
 import Profiler from './Profiler/Profiler';
 import TabBar from './TabBar';
+import EditorPane from './Editor/EditorPane';
 import {SettingsContextController} from './Settings/SettingsContext';
 import {TreeContextController} from './Components/TreeContext';
 import ViewElementSourceContext from './Components/ViewElementSourceContext';
@@ -51,6 +52,7 @@ import type {HookNamesModuleLoaderFunction} from 'react-devtools-shared/src/devt
 import type {FrontendBridge} from 'react-devtools-shared/src/bridge';
 import type {BrowserTheme} from 'react-devtools-shared/src/frontend/types';
 import type {ReactFunctionLocation} from 'shared/ReactTypes';
+import type {SourceSelection} from './Editor/EditorPane';
 
 export type TabID = 'components' | 'profiler';
 
@@ -97,6 +99,8 @@ export type Props = {
   // but individual tabs (e.g. Components, Profiling) can be rendered into portals within their browser panels.
   componentsPortalContainer?: Element,
   profilerPortalContainer?: Element,
+  editorPortalContainer?: Element,
+  currentSelectedSource?: null | SourceSelection,
 
   // Loads and parses source maps for function components
   // and extracts hook "names" based on the variables the hook return values get assigned to.
@@ -126,12 +130,14 @@ export default function DevTools({
   browserTheme = 'light',
   canViewElementSourceFunction,
   componentsPortalContainer,
+  profilerPortalContainer,
+  editorPortalContainer,
+  currentSelectedSource,
   defaultTab = 'components',
   enabledInspectedElementContextMenu = false,
   fetchFileWithCaching,
   hookNamesModuleLoaderFunction,
   overrideTab,
-  profilerPortalContainer,
   showTabBar = false,
   store,
   warnIfLegacyBackendDetected = false,
@@ -316,6 +322,12 @@ export default function DevTools({
                                     />
                                   </div>
                                 </div>
+                                {editorPortalContainer ? (
+                                  <EditorPane
+                                    selectedSource={currentSelectedSource}
+                                    portalContainer={editorPortalContainer}
+                                  />
+                                ) : null}
                               </ThemeProvider>
                             </InspectedElementContextController>
                           </TimelineContextController>

packages/react-devtools-shared/src/devtools/views/Editor/EditorPane.css

@@ -0,0 +1,28 @@
+.EditorPane {
+  position: relative;
+  display: flex;
+  flex-direction: row;
+  background-color: var(--color-background);
+  color: var(--color-text);
+  font-family: var(--font-family-sans);
+  align-items: center;
+  padding: 0.5rem;
+}
+
+.EditorPane, .EditorPane * {
+  box-sizing: border-box;
+  -webkit-font-smoothing: var(--font-smoothing);
+}
+
+.VRule {
+  height: 20px;
+  width: 1px;
+  flex: 0 0 1px;
+  margin: 0 0.5rem;
+  background-color: var(--color-border);
+}
+
+.WideButton {
+  flex: 1 0 auto;
+  display: flex;
+}