From 6506c1ce96cf44ab3917c9b2952a5aa3afbe13df Mon Sep 17 00:00:00 2001
From: Tim Neutkens <tim@timneutkens.nl>
Date: Thu, 14 Sep 2023 21:02:43 +0200
Subject: [PATCH] Memoize serverDistDir generation (#55375)

Was looking into the CPU profiles for `next start` and noticed this work kept being repeated. This reuses instead.
---
 packages/next/src/server/next-server.ts | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/packages/next/src/server/next-server.ts b/packages/next/src/server/next-server.ts
index ad7b8034b2b40..f5d3d7feb62eb 100644
--- a/packages/next/src/server/next-server.ts
+++ b/packages/next/src/server/next-server.ts
@@ -145,6 +145,7 @@ function getMiddlewareMatcher(
 }
 
 export default class NextNodeServer extends BaseServer {
+  private _serverDistDir: string | undefined
   private imageResponseCache?: ResponseCache
   protected renderWorkersPromises?: Promise<void>
   protected renderWorkerOpts?: Parameters<
@@ -1886,8 +1887,13 @@ export default class NextNodeServer extends BaseServer {
     return result
   }
 
-  protected get serverDistDir() {
-    return join(this.distDir, SERVER_DIRECTORY)
+  protected get serverDistDir(): string {
+    if (this._serverDistDir) {
+      return this._serverDistDir
+    }
+    const serverDistDir = join(this.distDir, SERVER_DIRECTORY)
+    this._serverDistDir = serverDistDir
+    return serverDistDir
   }
 
   protected async getFallbackErrorComponents(): Promise<LoadComponentsReturnType | null> {