refactor(serve): simplify static server setup

Read the 404 page with fs/promises, replace the trimChar helper with
a regex, and flatten the if/else around listen.

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

src/node/serve/serve.ts

@@ -1,22 +1,10 @@
 import compression from '@polka/compression'
-import fs from 'node:fs'
+import { readFile } from 'node:fs/promises'
 import path from 'node:path'
 import polka, { type IOptions } from 'polka'
 import sirv from 'sirv'
 import { resolveConfig } from '../config'
 
-function trimChar(str: string, char: string) {
-  while (str.charAt(0) === char) {
-    str = str.substring(1)
-  }
-
-  while (str.charAt(str.length - 1) === char) {
-    str = str.substring(0, str.length - 1)
-  }
-
-  return str
-}
-
 export interface ServeOptions {
   base?: string
   root?: string
@@ -26,14 +14,20 @@ export interface ServeOptions {
 export async function serve(options: ServeOptions = {}) {
   const port = options.port ?? 4173
   const config = await resolveConfig(options.root, 'serve', 'production')
-  const base = trimChar(options?.base ?? config?.site?.base ?? '', '/')
+  const base = (options?.base ?? config?.site?.base ?? '').replace(
+    /^\/+|\/+$/g,
+    ''
+  )
 
   const notAnAsset = (pathname: string) =>
     !pathname.includes(`/${config.assetsDir}/`)
-  const notFound = fs.readFileSync(path.resolve(config.outDir, './404.html'))
+  const notFound = await readFile(
+    path.resolve(config.outDir, './404.html'),
+    'utf8'
+  )
   const onNoMatch: IOptions['onNoMatch'] = (req, res) => {
     res.statusCode = 404
-    if (notAnAsset(req.path)) res.write(notFound.toString())
+    if (notAnAsset(req.path)) res.write(notFound)
     res.end()
   }
 
@@ -59,11 +53,11 @@ export async function serve(options: ServeOptions = {}) {
           `Built site served at http://localhost:${port}/${base}/`
         )
       })
-  } else {
+  }
+
   return polka({ onNoMatch })
     .use(compress, serve)
     .listen(port, () => {
       config.logger.info(`Built site served at http://localhost:${port}/`)
     })
-  }
 }