show error for next.js versions older than v14 (#237)

Author: james-elicx

.changeset/stupid-geese-reply.md

@@ -0,0 +1,5 @@
+---
+"@opennextjs/cloudflare": patch
+---
+
+show error on Next.js versions older than v14

packages/cloudflare/src/cli/build/index.ts

@@ -55,6 +55,7 @@ export async function build(projectOpts: ProjectOptions): Promise<void> {
   buildHelper.checkRunningInsideNextjsApp(options);
   logger.info(`App directory: ${options.appPath}`);
   buildHelper.printNextjsVersion(options);
+  ensureNextjsVersionSupported(options);
   buildHelper.printOpenNextVersion(options);
 
   if (projectOpts.skipNextBuild) {
@@ -276,3 +277,10 @@ export async function getLatestCompatDate(): Promise<string | undefined> {
     /* empty */
   }
 }
+
+function ensureNextjsVersionSupported(options: buildHelper.BuildOptions) {
+  if (buildHelper.compareSemver(options.nextVersion, "14.0.0") < 0) {
+    logger.error("Next.js version unsupported, please upgrade to version 14 or greater.");
+    process.exit(1);
+  }
+}