feat(preload): support bundling multiple preload scripts without requiring sandbox: false

src/build.ts

@@ -1,5 +1,5 @@
 import { build as viteBuild } from 'vite'
-import { type InlineConfig, resolveConfig } from './config'
+import { type InlineConfig, resolveConfig, type InlineUserConfig } from './config'
 
 /**
  * Bundles the electron app for production.
@@ -10,24 +10,26 @@ export async function build(inlineConfig: InlineConfig = {}): Promise<void> {
   if (config.config) {
     const mainViteConfig = config.config?.main
     if (mainViteConfig) {
-      if (mainViteConfig.build?.watch) {
-        mainViteConfig.build.watch = null
-      }
-      await viteBuild(mainViteConfig)
+      await _build(mainViteConfig)
     }
     const preloadViteConfig = config.config?.preload
     if (preloadViteConfig) {
-      if (preloadViteConfig.build?.watch) {
-        preloadViteConfig.build.watch = null
+      if (Array.isArray(preloadViteConfig)) {
+        await Promise.all(preloadViteConfig.map(_build))
+      } else {
+        await _build(preloadViteConfig)
       }
-      await viteBuild(preloadViteConfig)
     }
     const rendererViteConfig = config.config?.renderer
     if (rendererViteConfig) {
-      if (rendererViteConfig.build?.watch) {
-        rendererViteConfig.build.watch = null
-      }
-      await viteBuild(rendererViteConfig)
+      _build(rendererViteConfig)
     }
   }
 }
+
+async function _build(config: InlineUserConfig): Promise<void> {
+  if (config.build?.watch) {
+    config.build.watch = null
+  }
+  await viteBuild(config)
+}

src/config.ts

@@ -25,25 +25,27 @@ import { isObject, isFilePathESM } from './utils'
 
 export { defineConfig as defineViteConfig } from 'vite'
 
+export type InlineUserConfig = ViteConfig & { configFile?: string | false }
+
 export interface UserConfig {
   /**
    * Vite config options for electron main process
    *
    * https://vitejs.dev/config/
    */
-  main?: ViteConfig & { configFile?: string | false }
+  main?: InlineUserConfig
   /**
    * Vite config options for electron renderer process
    *
    * https://vitejs.dev/config/
    */
-  renderer?: ViteConfig & { configFile?: string | false }
+  renderer?: InlineUserConfig
   /**
    * Vite config options for electron preload files
    *
    * https://vitejs.dev/config/
    */
-  preload?: ViteConfig & { configFile?: string | false }
+  preload?: InlineUserConfig | InlineUserConfig[]
 }
 
 export interface ElectronViteConfig {
@@ -64,7 +66,7 @@ export interface ElectronViteConfig {
    *
    * https://vitejs.dev/config/
    */
-  preload?: ViteConfigExport
+  preload?: ViteConfigExport | ViteConfigExport[]
 }
 
 export type InlineConfig = Omit<ViteConfig, 'base'> & {
@@ -160,22 +162,30 @@ export async function resolveConfig(
       }
 
       if (loadResult.config.preload) {
-        const preloadViteConfig: ViteConfig = mergeConfig(loadResult.config.preload, deepClone(config))
+        if (Array.isArray(loadResult.config.preload)) {
+          loadResult.config.preload = loadResult.config.preload.map(normalizePreloadViteConfig)
+        } else {
+          loadResult.config.preload = normalizePreloadViteConfig(loadResult.config.preload)
+        }
 
-        preloadViteConfig.mode = inlineConfig.mode || preloadViteConfig.mode || defaultMode
+        function normalizePreloadViteConfig(preloadConfig: InlineUserConfig): InlineUserConfig {
+          const preloadViteConfig: InlineUserConfig = mergeConfig(preloadConfig, deepClone(config))
 
-        if (outDir) {
-          resetOutDir(preloadViteConfig, outDir, 'preload')
-        }
-        mergePlugins(preloadViteConfig, [
-          ...electronPreloadVitePlugin({ root }),
-          assetPlugin(),
-          importMetaPlugin(),
-          esmShimPlugin()
-        ])
+          preloadViteConfig.mode = inlineConfig.mode || preloadViteConfig.mode || defaultMode
+          preloadViteConfig.configFile = false
 
-        loadResult.config.preload = preloadViteConfig
-        loadResult.config.preload.configFile = false
+          if (outDir) {
+            resetOutDir(preloadViteConfig, outDir, 'preload')
+          }
+          mergePlugins(preloadViteConfig, [
+            ...electronPreloadVitePlugin({ root }),
+            assetPlugin(),
+            importMetaPlugin(),
+            esmShimPlugin()
+          ])
+
+          return preloadViteConfig
+        }
       }
 
       if (loadResult.config.renderer) {
@@ -299,8 +309,8 @@ export async function loadConfigFromFile(
     if (config.preload) {
       const preloadViteConfig = config.preload
       preloadConfig = await (typeof preloadViteConfig === 'function' ? preloadViteConfig(configEnv) : preloadViteConfig)
-      if (!isObject(preloadConfig)) {
-        throw new Error(`preload config must export or return an object`)
+      if (!isObject(preloadConfig) && (!Array.isArray(preloadConfig) || !preloadConfig.every(isObject))) {
+        throw new Error(`preload config must export or return an object or an array of objects`)
       }
     } else {
       configRequired.push('preload')

src/server.ts

@@ -1,14 +1,13 @@
 import type { ChildProcess } from 'node:child_process'
 import {
-  type UserConfig as ViteConfig,
   type ViteDevServer,
   createServer as viteCreateServer,
   build as viteBuild,
   createLogger,
   mergeConfig
 } from 'vite'
 import colors from 'picocolors'
-import { type InlineConfig, resolveConfig } from './config'
+import { type InlineConfig, resolveConfig, type InlineUserConfig } from './config'
 import { resolveHostname } from './utils'
 import { startElectron } from './electron'
 
@@ -53,7 +52,14 @@ export async function createServer(
     if (preloadViteConfig && !options.rendererOnly) {
       logger.info(colors.gray(`\n-----\n`))
 
+      let resolvedCount = 0
       const watchHook = (): void => {
+        resolvedCount++
+        if (Array.isArray(preloadViteConfig) && resolvedCount < preloadViteConfig.length) {
+          // Only resolve when all preload scripts are built
+          return
+        }
+
         logger.info(colors.green(`\nrebuild the electron preload files successfully`))
 
         if (server) {
@@ -63,7 +69,11 @@ export async function createServer(
         }
       }
 
-      await doBuild(preloadViteConfig, watchHook, errorHook)
+      if (Array.isArray(preloadViteConfig)) {
+        await Promise.all(preloadViteConfig.map(config => doBuild(config, watchHook, errorHook)))
+      } else {
+        await doBuild(preloadViteConfig, watchHook, errorHook)
+      }
 
       logger.info(colors.green(`\nbuild the electron preload files successfully`))
     }
@@ -110,9 +120,7 @@ export async function createServer(
   }
 }
 
-type UserConfig = ViteConfig & { configFile?: string | false }
-
-async function doBuild(config: UserConfig, watchHook: () => void, errorHook: (e: Error) => void): Promise<void> {
+async function doBuild(config: InlineUserConfig, watchHook: () => void, errorHook: (e: Error) => void): Promise<void> {
   return new Promise(resolve => {
     if (config.build?.watch) {
       let firstBundle = true