fix: manualChunks deletion / override

src/utils.ts

@@ -0,0 +1,13 @@
+export const maybeMap = <I, O>(
+  value: I | I[],
+  modifier: (item: I) => O,
+): O | O[] => (Array.isArray(value) ? value.map(modifier) : modifier(value))
+
+export const omit = <T extends object, K extends keyof T>(
+  obj: T,
+  ...keys: K[]
+): Omit<T, K> => {
+  const ret = { ...obj }
+  keys.forEach((key) => delete ret[key])
+  return ret
+}

src/vitePrebuild.ts

@@ -65,21 +65,21 @@ export function getVitePrebuilder(userConfig?: InlineConfig | string) {
 
     debug(`Pre-building ${files.length} files with Vite.`)
 
-    await build(
-      mergeConfig(viteConfig, {
-        build: {
-          outDir: OUT_DIR,
-          emptyOutDir: true,
-          minify: false,
-          rollupOptions: {
-            input: files,
-            output: { entryFileNames: '[name].ts', format: 'es' },
-            treeshake: true,
-          },
+    const resolvedConfig: InlineConfig = mergeConfig(viteConfig, {
+      build: {
+        outDir: OUT_DIR,
+        emptyOutDir: true,
+        minify: false,
+        rollupOptions: {
+          input: files,
+          output: { entryFileNames: '[name].ts', format: 'es' },
+          treeshake: true,
         },
-        esbuild: { treeShaking: true },
-      } satisfies InlineConfig),
-    )
+      },
+      esbuild: { treeShaking: true },
+    } satisfies InlineConfig)
+
+    await build(resolvedConfig)
   }
 
   function customVitePreprocessor(file: Cypress.FileObject) {

src/vitePreprocessor.ts

@@ -1,7 +1,8 @@
 import path from 'path'
-import { build, type InlineConfig } from 'vite'
+import { build, type BuildEnvironmentOptions, type InlineConfig } from 'vite'
 import chokidar from 'chokidar'
 import { debug, getConfig, type CypressPreprocessor } from './common'
+import { maybeMap, omit } from './utils'
 
 const watchers: Record<string, chokidar.FSWatcher> = {}
 
@@ -78,20 +79,42 @@ function vitePreprocessor(
           formats: ['umd'],
           name: filenameWithoutExtension,
         },
-        rollupOptions: {
-          output: {
-            // override any manualChunks from the user config because they don't work with UMD
-            // eslint-disable-next-line @typescript-eslint/no-explicit-any
-            manualChunks: false as any,
-          },
-        },
       },
     }
 
-    await build({
+    const resolvedConfig: InlineConfig & {
+      build?: InlineConfig['build'] & {
+        // `rolldownOptions` is used instead of `rollupOptions` in Vite 8.
+        // Just copy the type from `rollupOptions`, so we don't have to
+        // maintain another type or install another package.
+        rolldownOptions?: BuildEnvironmentOptions['rollupOptions']
+      }
+    } = {
       ...config,
       ...defaultConfig,
-    })
+    }
+
+    // Remove any manualChunks or advancedChunks.
+    for (const key of ['rollupOptions', 'rolldownOptions'] as const) {
+      if (resolvedConfig.build?.[key]?.output) {
+        resolvedConfig.build[key].output = maybeMap(
+          resolvedConfig.build[key].output,
+          (o) =>
+            omit(
+              o as typeof o & {
+                manualChunks?: unknown
+                advancedChunks?: unknown
+                codeSplitting?: unknown
+              },
+              'manualChunks',
+              'advancedChunks',
+              'codeSplitting',
+            ),
+        )
+      }
+    }
+
+    await build(resolvedConfig)
 
     return outputPath
   }