fix(serve): respect base config in serve mode (#470)

Fixes #416

Signed-off-by: Gordon Smith <GordonJSmith@gmail.com>

src/node/serve/serve.ts

@@ -3,6 +3,18 @@ import compression from 'compression'
 import { resolveConfig } from '../config'
 import polka from 'polka'
 
+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 {
   root?: string
   port?: number
@@ -11,6 +23,7 @@ export interface ServeOptions {
 export async function serve(options: ServeOptions = {}) {
   const port = options.port !== undefined ? options.port : 5000
   const site = await resolveConfig(options.root, 'serve', 'production')
+  const base = trimChar(site?.site?.base ?? "", "/")
 
   const compress = compression()
   const serve = sirv(site.outDir, {
@@ -27,10 +40,19 @@ export async function serve(options: ServeOptions = {}) {
     }
   })
 
+  if (base) {
+    polka()
+      .use(base, compress, serve)
+      .listen(port, (err: any) => {
+        if (err) throw err
+        console.log(`Built site served at http://localhost:${port}/${base}/\n`)
+      })
+  } else {
     polka()
       .use(compress, serve)
       .listen(port, (err: any) => {
         if (err) throw err
         console.log(`Built site served at http://localhost:${port}/\n`)
       })
+  }
 }