feat: electron next dev serve

electron/main/app.ts

@@ -1,7 +1,8 @@
 import type { Event } from 'electron';
 import { BrowserWindow, app, dialog, shell } from 'electron';
 import path from 'node:path';
-import serve from 'electron-serve';
+import prodServe from 'electron-serve';
+import trimEnd from 'lodash-es/trimEnd.js';
 import { runInBackground } from '../common/async/run-in-background.js';
 import type { IpcController } from './ipc/ipc.controller.js';
 import { newIpcController } from './ipc/ipc.controller.js';
@@ -25,7 +26,14 @@ const appEnvIsDev = appEnv === 'development';
 // Only load dev tools when running in development.
 const appEnableDevTools = appEnvIsDev && !app.isPackaged;
 
-const appPath = app.getAppPath();
+// When we migrated to ESM, the app path changed.
+// Instead of being at the root of the project, it's the directory
+// where this code file was invoked at runtime.
+// As a workaround, we trim off the extra path segments.
+const appPath = trimEnd(
+  app.getAppPath(),
+  path.join('electron', 'build', 'main')
+);
 const appElectronPath = path.join(appPath, 'electron');
 const appBuildPath = path.join(appElectronPath, 'build');
 const appPreloadPath = path.join(appBuildPath, 'preload');
@@ -42,13 +50,22 @@ const devAppUrl = `http://localhost:${devPort}`;
 
 const appUrl = appEnvIsProd ? prodAppUrl : devAppUrl;
 
+logger.debug('app paths', {
+  appPath,
+  appElectronPath,
+  appBuildPath,
+  appPreloadPath,
+  prodRendererPath,
+  devRendererPath,
+});
+
 // Register custom protocol 'app://' to serve our app.
 // Registering the protocol must be done before the app is ready.
 // This is necessary for both security and for single-page apps.
 // https://bishopfox.com/blog/reasonably-secure-electron
 // https://github.com/sindresorhus/electron-serve
 if (appEnvIsProd) {
-  serve({
+  prodServe({
     scheme: prodAppScheme,
     directory: prodRendererPath,
   });
@@ -63,10 +80,10 @@ const createMainWindow = async (): Promise<void> => {
     // If running in development, serve the renderer from localhost.
     // This must be done once the app is ready.
     // This enables hot reloading of the renderer.
-    const { serve } = await import('./electron-next/dev-server.js');
-    await serve({
-      rendererPath: devRendererPath,
+    const { devServe } = await import('./electron-next/dev-server.js');
+    await devServe({
       port: devPort,
+      directory: devRendererPath,
     });
   }
 

electron/main/electron-next/dev-server.ts

@@ -11,19 +11,24 @@ import { app } from 'electron';
 import * as http from 'node:http';
 import type { NextServer, NextServerOptions } from 'next/dist/server/next.js';
 import { runInBackground } from '../../common/async/run-in-background.js';
-import { sleep } from '../../common/async/sleep.js';
+import { logger } from './logger.js';
 
-export const serve = async (options: {
+export const devServe = async (options: {
   /**
-   * Path to the renderer directory, the root of your nextjs web app.
+   * The directory to serve, relative to the app root directory.
    */
-  rendererPath: string;
+  directory: string;
   /**
    * The port to serve the renderer on.
    */
   port: number;
 }): Promise<void> => {
-  const { rendererPath, port = 3000 } = options;
+  const { directory, port = 3000 } = options;
+
+  logger.info('starting nextjs dev server', {
+    directory,
+    port,
+  });
 
   // Dynamically import nextjs to avoid bundling it with the app
   // when webpack compiles and tree-shakes the project.
@@ -33,16 +38,13 @@ export const serve = async (options: {
     options: NextServerOptions
   ) => NextServer;
 
-  const nextServer = createNextServer({ dev: true, dir: rendererPath });
+  const nextServer = createNextServer({ dev: true, dir: directory });
 
   const requestHandler = nextServer.getRequestHandler();
 
   // Build the renderer code and watch the files.
   await nextServer.prepare();
 
-  console.log('nextjs server is ready');
-  await sleep(30_000);
-
   // Create a new native HTTP server to support hot code reloading.
   const httpServer = http.createServer(
     (req: http.IncomingMessage, res: http.ServerResponse) => {
@@ -55,6 +57,9 @@ export const serve = async (options: {
   httpServer.listen(port, () => {
     // Make sure to stop the server when the app closes.
     // Otherwise it keeps running on its own.
-    app.on('before-quit', () => httpServer.close());
+    app.once('before-quit', () => {
+      logger.info('stopping nextjs dev server');
+      httpServer.close();
+    });
   });
 };

electron/main/electron-next/logger.ts

@@ -0,0 +1,5 @@
+import { createLogger } from '../logger/create-logger.js';
+
+const logger = await createLogger('main:electron-next');
+
+export { logger };

next.config.js

@@ -214,7 +214,7 @@ const nextConfig = {
     if (!config.resolve) {
       config.resolve = {};
     }
-    config.resolve.mainFields = ['module', 'main'];
+    config.resolve.mainFields = ['module', 'main', 'exports'];
 
     // Add extension aliases to support ESM-style imports.
     // https://github.com/vercel/next.js/issues/41961