feat: add support for --experimental-transform-types (#49881)

* feat: add support for `--experimental-transform-types`

Co-authored-by: Niklas Wenzel <dev@nikwen.de>

* chore: add tests

Co-authored-by: Niklas Wenzel <dev@nikwen.de>

* docs: add `--experimental-transform-types` to docs

Co-authored-by: Niklas Wenzel <dev@nikwen.de>

---------

Co-authored-by: trop[bot] <37223003+trop[bot]@users.noreply.github.com>
Co-authored-by: Niklas Wenzel <dev@nikwen.de>

docs/api/command-line-switches.md

@@ -345,6 +345,11 @@ Affects the default output directory of [v8.setHeapSnapshotNearHeapLimit](https:
 
 Disable exposition of [Navigator API][] on the global scope from Node.js.
 
+### `--experimental-transform-types`
+
+Enables the [transformation](https://nodejs.org/api/typescript.html#type-stripping)
+of TypeScript-only syntax into JavaScript code.
+
 ## Chromium Flags
 
 There isn't a documented list of all Chromium switches, but there are a few ways to find them.

script/release/uploaders/upload.py

@@ -367,6 +367,9 @@ def upload_io_to_github(release, filename, filepath, version):
       for c in iter(lambda: upload_process.stdout.read(1), b""):
         sys.stdout.buffer.write(c)
         sys.stdout.flush()
+    upload_process.wait()
+    if upload_process.returncode != 0:
+      sys.exit(upload_process.returncode)
 
   if "GITHUB_OUTPUT" in os.environ:
     output_path = os.environ["GITHUB_OUTPUT"]

shell/browser/api/electron_api_web_contents.cc

@@ -4645,6 +4645,19 @@ gin_helper::Handle<WebContents> WebContents::CreateFromWebPreferences(
       existing_preferences->SetFromDictionary(web_preferences_dict);
       web_contents->SetBackgroundColor(
           existing_preferences->GetBackgroundColor());
+
+      double zoom_factor;
+      if (web_preferences.Get(options::kZoomFactor, &zoom_factor)) {
+        auto* zoom_controller = WebContentsZoomController::FromWebContents(
+            web_contents->web_contents());
+        if (zoom_controller) {
+          zoom_controller->SetDefaultZoomFactor(zoom_factor);
+          // Also set the current zoom level immediately, since the page
+          // has already navigated by the time we wrap the webContents.
+          zoom_controller->SetZoomLevel(
+              blink::ZoomFactorToZoomLevel(zoom_factor));
+        }
+      }
     }
   } else {
     // Create one if not.

shell/common/node_bindings.cc

@@ -412,6 +412,7 @@ bool IsAllowedOption(const std::string_view option) {
           "--inspect-port",
           "--inspect-publish-uid",
           "--experimental-network-inspection",
+          "--experimental-transform-types",
       });
 
   // This should be aligned with what's possible to set via the process object.

spec/api-browser-window-spec.ts

@@ -3983,6 +3983,28 @@ describe('BrowserWindow module', () => {
         expect(webPreferences!.contextIsolation).to.equal(false);
       });
 
+      it('should apply zoomFactor from setWindowOpenHandler overrideBrowserWindowOptions', async () => {
+        const w = new BrowserWindow({
+          show: false,
+          webPreferences: {
+            sandbox: true
+          }
+        });
+
+        w.webContents.setWindowOpenHandler(() => ({
+          action: 'allow',
+          overrideBrowserWindowOptions: {
+            webPreferences: {
+              zoomFactor: 2.0
+            }
+          }
+        }));
+        w.loadFile(path.join(fixtures, 'api', 'new-window.html'));
+        const [childWindow] = await once(w.webContents, 'did-create-window') as [BrowserWindow, any];
+        await once(childWindow.webContents, 'did-finish-load');
+        expect(childWindow.webContents.getZoomFactor()).to.be.closeTo(2.0, 0.1);
+      });
+
       it('should set ipc event sender correctly', async () => {
         const w = new BrowserWindow({
           show: false,

spec/fixtures/type-stripping/basic.ts

@@ -0,0 +1,7 @@
+import { app } from 'electron/main';
+
+const logMessage = (message: string): void => console.log(message);
+
+logMessage('running');
+
+app.exit(0);

spec/fixtures/type-stripping/transform-types-node.ts

@@ -0,0 +1,9 @@
+enum Test {
+  A,
+  B,
+  C,
+}
+
+console.log(Test.A);
+
+process.exit(0);

spec/fixtures/type-stripping/transform-types.ts

@@ -0,0 +1,11 @@
+import { app } from 'electron/main';
+
+enum Test {
+  A,
+  B,
+  C,
+}
+
+console.log(Test.A);
+
+app.exit(0);

spec/node-spec.ts

@@ -1030,4 +1030,26 @@ describe('node feature', () => {
       });
     });
   });
+
+  describe('type stripping', () => {
+    it('strips TypeScript types automatically in the main process', async () => {
+      const child = childProcess.spawn(process.execPath, [path.join(fixtures, 'type-stripping', 'basic.ts')]);
+      const [code] = await once(child, 'exit');
+      expect(code).to.equal(0);
+    });
+
+    it('will not transform TypeScript types without --experimental-transform-types', async () => {
+      const child = childProcess.spawn(process.execPath, [path.join(fixtures, 'type-stripping', 'transform-types-node.ts')], {
+        env: { ELECTRON_RUN_AS_NODE: 'true' }
+      });
+      const [code] = await once(child, 'exit');
+      expect(code).to.not.equal(0);
+    });
+
+    it('transforms TypeScript types with --experimental-transform-types', async () => {
+      const child = childProcess.spawn(process.execPath, ['--experimental-transform-types', path.join(fixtures, 'type-stripping', 'transform-types.ts')]);
+      const [code] = await once(child, 'exit');
+      expect(code).to.equal(0);
+    });
+  });
 });