add helper function

Author: sommeeeer

packages/open-next/src/build/compileConfig.ts

@@ -6,7 +6,7 @@ import { buildSync } from "esbuild";
 import type { OpenNextConfig } from "types/open-next.js";
 
 import logger from "../logger.js";
-import { DEV_CONFIG } from "./constant.js";
+import { buildDevConfig } from "./helper.js";
 import { validateConfig } from "./validateConfig.js";
 
 /**
@@ -77,25 +77,19 @@ export function compileOpenNextConfigNode(
   const outputPath = path.join(outputDir, "open-next.config.mjs");
   logger.debug("Compiling open-next.config.ts for Node.", outputPath);
 
+  if (dev) {
+    buildDevConfig(outputPath, externals);
+    return outputPath;
+  }
+
   //Check if open-next.config.ts exists
   if (!fs.existsSync(sourcePath)) {
     //Create a simple open-next.config.mjs file
     logger.debug("Cannot find open-next.config.ts. Using default config.");
     fs.writeFileSync(outputPath, "export default { default: { } };");
   } else {
     buildSync({
-      ...(dev
-        ? {
-            stdin: {
-              contents: DEV_CONFIG,
-              resolveDir: process.cwd(),
-              loader: "ts",
-              sourcefile: "open-next.config.ts",
-            },
-          }
-        : {
-            entryPoints: [sourcePath],
-          }),
+      entryPoints: [sourcePath],
       outfile: outputPath,
       bundle: true,
       format: "esm",

packages/open-next/src/build/helper.ts

@@ -11,6 +11,7 @@ import type {
 } from "types/open-next.js";
 
 import logger from "../logger.js";
+import { DEV_CONFIG } from "./constant.js";
 
 const require = createRequire(import.meta.url);
 const __dirname = url.fileURLToPath(new URL(".", import.meta.url));
@@ -440,3 +441,28 @@ export async function isEdgeRuntime(
 export function getPackagePath(options: BuildOptions) {
   return path.relative(options.monorepoRoot, options.appBuildOutputPath);
 }
+
+export function buildDevConfig(outputPath: string, externals: string[]) {
+  buildSync({
+    stdin: {
+      contents: DEV_CONFIG,
+      resolveDir: process.cwd(),
+      loader: "ts",
+      sourcefile: "open-next.config.ts",
+    },
+    outfile: outputPath,
+    bundle: true,
+    format: "esm",
+    target: ["node18"],
+    external: externals,
+    platform: "node",
+    banner: {
+      js: [
+        "import { createRequire as topLevelCreateRequire } from 'module';",
+        "const require = topLevelCreateRequire(import.meta.url);",
+        "import bannerUrl from 'url';",
+        "const __dirname = bannerUrl.fileURLToPath(new URL('.', import.meta.url));",
+      ].join(""),
+    },
+  });
+}