refactor: vite-loader util (#1294)

split from #1281.

Author: dai-shi

packages/waku/src/cli.ts

@@ -220,7 +220,7 @@ async function loadConfig(): Promise<Config> {
   if (!existsSync(CONFIG_FILE)) {
     return {};
   }
-  const { loadServerFile } = await import('./lib/utils/vite-loader.js');
+  const { loadServerModule } = await import('./lib/utils/vite-loader.js');
   const file = pathToFileURL(path.resolve(CONFIG_FILE)).toString();
-  return (await loadServerFile(file)).default;
+  return (await loadServerModule<{ default: Config }>(file)).default;
 }

packages/waku/src/lib/utils/vite-loader.ts

@@ -3,7 +3,11 @@ import type { RunnableDevEnvironment } from 'vite';
 
 import { fileURLToFilePath } from '../utils/path.js';
 
-export const loadServerFile = async (fileURL: string) => {
+export const loadServerModule = async <T>(idOrFileURL: string): Promise<T> => {
+  if (idOrFileURL === 'waku' || idOrFileURL.startsWith('waku/')) {
+    // HACK `external: ['waku']` doesn't do the same
+    return import(idOrFileURL) as T;
+  }
   const vite = await createViteServer({
     server: { middlewareMode: true, watch: null },
     appType: 'custom',
@@ -21,6 +25,10 @@ export const loadServerFile = async (fileURL: string) => {
   );
   const mod = await (
     vite.environments.config as RunnableDevEnvironment
-  ).runner.import(fileURLToFilePath(fileURL));
-  return mod;
+  ).runner.import(
+    idOrFileURL.startsWith('file://')
+      ? fileURLToFilePath(idOrFileURL)
+      : idOrFileURL,
+  );
+  return mod as T;
 };