generate robots.txt dynamically

src/app/robots.ts

@@ -0,0 +1,14 @@
+import { getGitInfo } from "@/utils/git-info";
+import { MetadataRoute } from "next";
+
+export default async function robots(): Promise<MetadataRoute.Robots> {
+  const gitInfo = await getGitInfo()
+  const isDevWebsite = gitInfo?.isDev ?? false
+
+  return {
+    rules: {
+      userAgent: '*',
+      [isDevWebsite ? 'disallow' : 'allow']: '/',
+    },
+  }
+}

src/utils/git-info.ts

@@ -33,7 +33,7 @@ async function tryGetGitInfoFromCommand(): Promise<GitInfo | undefined> {
     if (branch && commitHash) {
       return {
         branch, commitHash,
-        isDev: false,  // treat local development environment as isDev=false
+        isDev: false,  // treat local development environment as the prod website
       }
     }
   } catch {