fix: EventEmitter is missing properties in sandbox preload script. (e…

…lectron#35522)

package.json

@@ -45,6 +45,7 @@
     "eslint-plugin-node": "^11.1.0",
     "eslint-plugin-standard": "^4.0.1",
     "eslint-plugin-typescript": "^0.14.0",
+    "events": "^3.2.0",
     "express": "^4.16.4",
     "folder-hash": "^2.1.1",
     "fs-extra": "^9.0.1",

spec/api-browser-window-spec.ts

@@ -2970,6 +2970,26 @@ describe('BrowserWindow module', () => {
         expect(url).to.equal(expectedUrl);
       });
 
+      it('exposes full EventEmitter object to preload script', async () => {
+        const w = new BrowserWindow({
+          show: false,
+          webPreferences: {
+            sandbox: true,
+            preload: path.join(fixtures, 'module', 'preload-eventemitter.js')
+          }
+        });
+        w.loadURL('about:blank');
+        const [, rendererEventEmitterProperties] = await emittedOnce(ipcMain, 'answer');
+        const { EventEmitter } = require('events');
+        const emitter = new EventEmitter();
+        const browserEventEmitterProperties = [];
+        let currentObj = emitter;
+        do {
+          browserEventEmitterProperties.push(...Object.getOwnPropertyNames(currentObj));
+        } while ((currentObj = Object.getPrototypeOf(currentObj)));
+        expect(rendererEventEmitterProperties).to.deep.equal(browserEventEmitterProperties);
+      });
+
       it('should open windows in same domain with cross-scripting enabled', async () => {
         const w = new BrowserWindow({
           show: true,

spec/fixtures/module/preload-eventemitter.js

@@ -0,0 +1,11 @@
+(function () {
+  const { EventEmitter } = require('events');
+  const emitter = new EventEmitter();
+  const rendererEventEmitterProperties = [];
+  let currentObj = emitter;
+  do {
+    rendererEventEmitterProperties.push(...Object.getOwnPropertyNames(currentObj));
+  } while ((currentObj = Object.getPrototypeOf(currentObj)));
+  const { ipcRenderer } = require('electron');
+  ipcRenderer.send('answer', rendererEventEmitterProperties);
+})();