refactor: consistently retrieve the build folder from the options

And a few other minor changes:
- rename BuildOptions#tempDir to BuildOptions#buildDir
- simplify the default OpenNext config
- rename a few arguments for consistency / clarity

Author: vicb

packages/open-next/src/build.ts

@@ -191,15 +191,12 @@ function initOutputDir(srcTempDir: string, options: BuildOptions) {
     );
   }
   fs.rmSync(options.outputDir, { recursive: true, force: true });
-  const destTempDir = options.tempDir;
-  fs.mkdirSync(destTempDir, { recursive: true });
-  fs.writeFileSync(
-    path.join(destTempDir, "open-next.config.mjs"),
-    openNextConfig,
-  );
+  const { buildDir } = options;
+  fs.mkdirSync(buildDir, { recursive: true });
+  fs.writeFileSync(path.join(buildDir, "open-next.config.mjs"), openNextConfig);
   if (openNextConfigEdge) {
     fs.writeFileSync(
-      path.join(destTempDir, "open-next.config.edge.mjs"),
+      path.join(buildDir, "open-next.config.edge.mjs"),
       openNextConfigEdge,
     );
   }
@@ -215,7 +212,7 @@ async function createWarmerBundle(options: BuildOptions) {
   fs.mkdirSync(outputPath, { recursive: true });
 
   // Copy open-next.config.mjs into the bundle
-  copyOpenNextConfig(options.tempDir, outputPath);
+  copyOpenNextConfig(options.buildDir, outputPath);
 
   // Build Lambda code
   // note: bundle in OpenNext package b/c the adatper relys on the
@@ -258,7 +255,7 @@ async function createRevalidationBundle(options: BuildOptions) {
   fs.mkdirSync(outputPath, { recursive: true });
 
   //Copy open-next.config.mjs into the bundle
-  copyOpenNextConfig(options.tempDir, outputPath);
+  copyOpenNextConfig(options.buildDir, outputPath);
 
   // Build Lambda code
   await esbuildAsync(
@@ -297,7 +294,7 @@ async function createImageOptimizationBundle(options: BuildOptions) {
   fs.mkdirSync(outputPath, { recursive: true });
 
   // Copy open-next.config.mjs into the bundle
-  copyOpenNextConfig(options.tempDir, outputPath);
+  copyOpenNextConfig(options.buildDir, outputPath);
 
   const plugins = [
     openNextResolvePlugin({
@@ -636,7 +633,7 @@ async function createCacheAssets(options: BuildOptions) {
       );
 
       //Copy open-next.config.mjs into the bundle
-      copyOpenNextConfig(options.tempDir, providerPath);
+      copyOpenNextConfig(options.buildDir, providerPath);
 
       // TODO: check if metafiles doesn't contain duplicates
       fs.writeFileSync(
@@ -660,7 +657,7 @@ export function compileCache(
 ) {
   const { config } = options;
   const ext = format === "cjs" ? "cjs" : "mjs";
-  const outfile = path.join(options.outputDir, ".build", `cache.${ext}`);
+  const outfile = path.join(options.buildDir, `cache.${ext}`);
 
   const isAfter15 = compareSemver(options.nextVersion, "15.0.0") >= 0;
 
@@ -721,7 +718,7 @@ async function createMiddleware(options: BuildOptions) {
 
     // Copy open-next.config.mjs
     copyOpenNextConfig(
-      options.tempDir,
+      options.buildDir,
       outputPath,
       config.middleware.override?.wrapper === "cloudflare",
     );
@@ -739,7 +736,7 @@ async function createMiddleware(options: BuildOptions) {
   } else {
     await buildEdgeBundle({
       entrypoint: path.join(__dirname, "core", "edgeFunctionHandler.js"),
-      outfile: path.join(outputDir, ".build", "middleware.mjs"),
+      outfile: path.join(options.buildDir, "middleware.mjs"),
       ...commonMiddlewareOptions,
       onlyBuildOnce: true,
     });

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

@@ -7,28 +7,21 @@ import { OpenNextConfig } from "types/open-next.js";
 import logger from "../logger.js";
 
 export function compileOpenNextConfigNode(
-  tempDir: string,
+  outputDir: string,
   openNextConfigPath?: string,
   nodeExternals?: string,
 ) {
   const sourcePath = path.join(
     process.cwd(),
     openNextConfigPath ?? "open-next.config.ts",
   );
-  const outputPath = path.join(tempDir, "open-next.config.mjs");
+  const outputPath = path.join(outputDir, "open-next.config.mjs");
 
   //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,
-      [
-        "var config = { default: { } };",
-        "var open_next_config_default = config;",
-        "export { open_next_config_default as default };",
-      ].join("\n"),
-    );
+    fs.writeFileSync(outputPath, "export default { default: { } };");
   } else {
     buildSync({
       entryPoints: [sourcePath],

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

@@ -144,7 +144,7 @@ async function generateBundle(
 
   const ext = fnOptions.runtime === "deno" ? "mjs" : "cjs";
   fs.copyFileSync(
-    path.join(outputDir, ".build", `cache.${ext}`),
+    path.join(options.buildDir, `cache.${ext}`),
     path.join(outputPath, packagePath, "cache.cjs"),
   );
 
@@ -158,24 +158,21 @@ async function generateBundle(
     await bundleNextServer(path.join(outputPath, packagePath), appPath);
   }
 
-  // // Copy middleware
+  // Copy middleware
   if (
     !config.middleware?.external &&
-    existsSync(path.join(outputDir, ".build", "middleware.mjs"))
+    existsSync(path.join(options.buildDir, "middleware.mjs"))
   ) {
     fs.copyFileSync(
-      path.join(outputDir, ".build", "middleware.mjs"),
+      path.join(options.buildDir, "middleware.mjs"),
       path.join(outputPath, packagePath, "middleware.mjs"),
     );
   }
 
   // Copy open-next.config.mjs
-  copyOpenNextConfig(
-    path.join(outputDir, ".build"),
-    path.join(outputPath, packagePath),
-  );
+  copyOpenNextConfig(options.buildDir, path.join(outputPath, packagePath));
 
-  //Copy env files
+  // Copy env files
   copyEnvFile(appBuildOutputPath, packagePath, outputPath);
 
   // Copy all necessary traced files

packages/open-next/src/build/edge/createEdgeBundle.ts

@@ -179,7 +179,7 @@ export async function generateEdgeBundle(
   fs.mkdirSync(outputPath, { recursive: true });
 
   // Copy open-next.config.mjs
-  copyOpenNextConfig(path.join(outputDir, ".build"), outputPath, true);
+  copyOpenNextConfig(options.buildDir, outputPath, true);
 
   // Load middleware manifest
   const middlewareManifest = JSON.parse(

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

@@ -51,7 +51,7 @@ export function normalizeOptions(config: OpenNextConfig) {
     openNextVersion: getOpenNextVersion(),
     outputDir,
     packager,
-    tempDir: path.join(outputDir, ".build"),
+    buildDir: path.join(outputDir, ".build"),
   };
 }
 
@@ -273,17 +273,17 @@ export function compareSemver(v1: string, v2: string): number {
 }
 
 export function copyOpenNextConfig(
-  tempDir: string,
-  outputPath: string,
+  inputDir: string,
+  outputDir: string,
   isEdge = false,
 ) {
   // Copy open-next.config.mjs
   fs.copyFileSync(
     path.join(
-      tempDir,
+      inputDir,
       isEdge ? "open-next.config.edge.mjs" : "open-next.config.mjs",
     ),
-    path.join(outputPath, "open-next.config.mjs"),
+    path.join(outputDir, "open-next.config.mjs"),
   );
 }