refactor: return the task callback result

Lets bundle() receive the build outputs from the spinner-wrapped
callback directly instead of smuggling them through outer let
bindings with a definite-assignment assertion.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/node/build/bundle.ts

@@ -172,16 +172,20 @@ export async function bundle(
     configFile: config.vite?.configFile
   })
 
-  let clientResult: Rolldown.RolldownOutput | null = null
-  let serverResult!: Rolldown.RolldownOutput
-
-  // prettier-ignore
-  await task('building client + server bundles', async () => {
-    if (!config.mpa) clientResult =
-      (await build(await resolveViteConfig(false))) as Rolldown.RolldownOutput
-    serverResult =
-      (await build(await resolveViteConfig(true))) as Rolldown.RolldownOutput
-  })
+  let { clientResult, serverResult } = await task(
+    'building client + server bundles',
+    async () => {
+      const clientResult = config.mpa
+        ? null
+        : ((await build(
+            await resolveViteConfig(false)
+          )) as Rolldown.RolldownOutput)
+      const serverResult = (await build(
+        await resolveViteConfig(true)
+      )) as Rolldown.RolldownOutput
+      return { clientResult, serverResult }
+    }
+  )
 
   if (config.mpa) {
     // in MPA mode, we need to copy over the non-js asset files from the

src/node/utils/task.ts

@@ -3,16 +3,21 @@ import ora from 'ora'
 export const okMark = '\x1b[32m✓\x1b[0m'
 export const failMark = '\x1b[31m✗\x1b[0m'
 
-export async function task(taskName: string, task: () => Promise<void>) {
+export async function task<T>(
+  taskName: string,
+  task: () => Promise<T>
+): Promise<T> {
   const spinner = ora({ discardStdin: false })
   spinner.start(taskName + '...')
 
+  let result: T
   try {
-    await task()
+    result = await task()
   } catch (e) {
     spinner.stopAndPersist({ symbol: failMark })
     throw e
   }
 
   spinner.stopAndPersist({ symbol: okMark })
+  return result
 }