Bump Electron to latest and enable native ESM

This commit bumps Electron (`electron`) and dependencies in its
ecosystem (`electron-builder` and `electron-log`) to their latest
versions.

It also adjusts the build configuration to enable native Electron ESM
support rather than relying on the bundler.

Key changes:

- Bump Electron to latest v29.
  Electron v28 ships with native ESM/ECMAScript modules support.
  Details on Electron ESM support:
   - electron/electron$21457
   - electron/electron$37535
- Bump `electron-builder` to latest v24.13.
  `electron-builder` is used to package and publish the application.
  It supports ESM since 24.10.
  Details on `electron-builder` ESM support:
  - electron-userland/electron-builder$7936
  - electron-userland/electron-builder$7935
- Bump `electron-log` to latest v5.1.
  `electron-log` supports ESM since version 5.0.4.
  Details on `electron-log` ESM support:
  - megahertz/electron-log$390.

Other supporting changes:

- Add type hint for electron-builder configuration file.
- Update import statements for `electron-updater` as it still is a
  CommonJS module and does not support ESM.
  Details: electron-userland/electron-builder$7976
- In `electron-builder` configuration, dynamically locate index file to
  accommodate different index file extensions outputted from bundling
  process such as `.js`, `.mjs` and `.cjs` to enable easier future
  changes.
- Remove Electron process specific module alias registration as the
  workaround is no longer necessary as it's fixed in mainstream.
  See alex8088/electron-vite$372. TODO: Not done yet
- With native Electron ESM support, Electron ESM loader cannot correctly
  resolve subpath modules. As a workaround, let `electron-vite` bundle
  `electron-log` so import from `electron-log/main` can be used.
  Details on workaround: alex8088/electron-vite$401
  Details on Electron problem: electron/electron$41241

electron-builder.cjs

@@ -1,8 +1,13 @@
 /* eslint-disable no-template-curly-in-string */
 
 const { join } = require('node:path');
+const { readdirSync } = require('fs');
 const { electronBundled, electronUnbundled } = require('./dist-dirs.json');
 
+/**
+* @type {import('electron-builder').Configuration}
+* @see https://www.electron.build/configuration/configuration
+*/
 module.exports = {
   // Common options
   publish: {
@@ -14,7 +19,9 @@ module.exports = {
     output: electronBundled,
   },
   extraMetadata: {
-    main: join(electronUnbundled, 'main/index.cjs'), // do not `path.resolve`, it expects a relative path
+    main: findMainEntryFile(
+      join(electronUnbundled, 'main'), // do not `path.resolve`, it expects a relative path
+    ),
   },
 
   // Windows
@@ -41,3 +48,15 @@ module.exports = {
     artifactName: '${name}-${version}.${ext}',
   },
 };
+
+/**
+ * Finds by accommodating different JS file extensions and module formats.
+ */
+function findMainEntryFile(parentDirectory) {
+  const files = readdirSync(parentDirectory);
+  const entryFile = files.find((file) => /^index\.(mjs|js)$/.test(file));
+  if (!entryFile) {
+    throw new Error(`Main entry file not found in ${parentDirectory}.`);
+  }
+  return join(parentDirectory, entryFile);
+}

electron.vite.config.ts

@@ -14,7 +14,7 @@ const ELECTRON_DIST_SUBDIRECTORIES = {
   renderer: resolveElectronDistSubdirectory('renderer'),
 };
 
-process.env.ELECTRON_ENTRY = resolve(ELECTRON_DIST_SUBDIRECTORIES.main, 'index.cjs');
+process.env.ELECTRON_ENTRY = resolve(ELECTRON_DIST_SUBDIRECTORIES.main, 'index.mjs');
 
 export default defineConfig({
   main: getSharedElectronConfig({
@@ -54,13 +54,23 @@ function getSharedElectronConfig(options: {
       },
       rollupOptions: {
         output: {
-          // Mark: electron-esm-support
-          //  This is needed so `type="module"` works
-          entryFileNames: '[name].cjs',
+          format: 'es',
+
+          // Enforce `.mjs` for all generated files.
+          // Otherwise, preloader process get `.mjs` extension but main process get `.js` extension, see https://github.com/alex8088/electron-vite/issues/397.
+          // This is used for consistency.
+          entryFileNames: '[name].mjs',
         },
       },
     },
-    plugins: [externalizeDepsPlugin()],
+    plugins: [externalizeDepsPlugin({
+      exclude: [
+        // Do not externalize `electron-log` so subpath imports such as `electron-log/main` works.
+        // It's a workaround as Electron ESM loader cannot correctly resolve subpath modules.
+        // See https://github.com/electron/electron/issues/41241, https://github.com/alex8088/electron-vite/issues/401
+        'electron-log',
+      ],
+    })],
     define: {
       ...getClientEnvironmentVariables(),
     },