/desktop-framework-electron

name: desktop-framework-electron
description: Electron process architecture, IPC patterns, preload security, native APIs, packaging and distribution

Electron Desktop Applications

> **Quick Guide:** Electron apps run two process types: a **main process** (Node.js, manages windows and system APIs) and **renderer processes** (Chromium, one per window). All communication between them flows through IPC via a preload script that uses `contextBridge` to expose a minimal, typed API surface. Never disable `contextIsolation`. Never enable `nodeIntegration` in renderers. Package with Electron Forge or Electron Builder. Auto-update via `autoUpdater` (Squirrel on macOS/Windows) or `electron-updater` for all platforms.

---

<critical_requirements>

CRITICAL: Before Using This Skill

> **All code must follow project conventions in CLAUDE.md** (kebab-case, named exports, import ordering, `import type`, named constants)

**(You MUST keep `contextIsolation: true` (the default) -- disabling it exposes the entire preload scope to untrusted renderer code)**

**(You MUST use `contextBridge.exposeInMainWorld()` in preload scripts -- never expose `ipcRenderer` directly)**

**(You MUST NOT enable `nodeIntegration: true` in any BrowserWindow -- it gives renderers full Node.js access, which is a critical security vulnerability)**

**(You MUST validate and sanitize ALL data received via IPC in the main process -- treat renderer messages as untrusted input)**

**(You MUST use `ipcMain.handle()` / `ipcRenderer.invoke()` for request-response IPC -- avoid `sendSync` which blocks the renderer)**

**(You MUST NOT load remote URLs with `nodeIntegration` or disabled `contextIsolation` -- this is equivalent to giving the remote site full system access)**

</critical_requirements>

---

**Auto-detection:** Electron, electron, BrowserWindow, ipcMain, ipcRenderer, contextBridge, preload, webPreferences, electron-builder, electron-forge, app.whenReady, electronAPI, mainWindow, autoUpdater, nativeTheme, safeStorage, Tray, Menu, dialog, protocol, shell

**When to use:**

• Building cross-platform desktop applications
• Configuring main process / renderer process architecture
• Setting up secure IPC communication patterns
• Integrating with native OS features (tray, menus, dialogs, notifications, file system)
• Packaging and distributing desktop applications
• Implementing auto-update functionality
• Registering custom protocol handlers / deep links

**When NOT to use:**

• Choosing a UI framework for the renderer (use the appropriate web framework skill)
• Styling the renderer UI (use the appropriate styling skill)
• Server-side or backend logic not related to the main process
• Mobile applications (Electron is desktop-only)
• CLI tools that do not need a GUI

---

<patterns>

Key Patterns

Pattern 1: Secure BrowserWindow Creation

Every BrowserWindow must use a preload script and rely on the secure defaults: `contextIsolation: true`, `sandbox: true`, `nodeIntegration: false`.

const mainWindow = new BrowserWindow({
  width: 1200,
  height: 800,
  webPreferences: {
    preload: path.join(__dirname, "preload.js"),
    // contextIsolation: true  -- default since Electron 12
    // sandbox: true           -- default since Electron 20
    // nodeIntegration: false  -- default since Electron 5
  },
});

**Key point:** Never override the security defaults. The preload script is the ONLY bridge between main and renderer. See [examples/core.md](examples/core.md).

---

Pattern 2: Preload with contextBridge

The preload script exposes a narrow, explicitly typed API to the renderer. Never expose `ipcRenderer` directly.

// preload.js
const { contextBridge, ipcRenderer } = require("electron");

contextBridge.exposeInMainWorld("electronAPI", {
  readFile: (filePath) => ipcRenderer.invoke("read-file", filePath),
  onUpdateAvailable: (callback) => {
    ipcRenderer.on("update-available", (_event, data) => callback(data));
  },
});

**Key point:** Each exposed method wraps a single IPC channel. The renderer calls `window.electronAPI.readFile(path)` with no knowledge of IPC internals. See [examples/core.md](examples/core.md).

---

Pattern 3: IPC Request-Response (invoke/handle)

Use `ipcMain.handle()` in main and `ipcRenderer.invoke()` in preload for async two-way communication.

// main process
ipcMain.handle("read-file", async (_event, filePath) => {
  const content = await fs.readFile(filePath, "utf-8");
  return { success: true, content };
});

**Key point:** `handle`/`invoke` returns a Promise. Always validate `filePath` in the handler -- never trust renderer input. See [examples/ipc.md](examples/ipc.md) for all IPC patterns.

---

Pattern 4: Main-to-Renderer Messages

Use `webContents.send()` from main and listen in the preload with a callback pattern.

// main: send to specific window
mainWindow.webContents.send("update-progress", { percent: 45 });

// preload: expose listener
onUpdateProgress: (callback) => {
  ipcRenderer.on("update-progress", (_event, data) => callback(data));
},

**Key point:** The renderer cannot pull from main -- main must push. Always scope listeners to specific channels. See [examples/ipc.md](examples/ipc.md).

---

Pattern 5: App Lifecycle

The main process manages the app lifecycle with platform-specific conventions.

app.whenReady().then(() => {
  createWindow();
  app.on("activate", () => {
    if (BrowserWindow.getAllWindows().length === 0) createWindow();
  });
});

app.on("window-all-closed", () => {
  if (process.platform !== "darwin") app.quit();
});

**Key point:** macOS apps stay alive when all windows close (`window-all-closed` should not quit). The `activate` event recreates a window when the dock icon is clicked. See [examples/core.md](examples/core.md).

---

Pattern 6: Native OS Integration

Electron exposes native APIs for dialogs, menus, tray icons, notifications,