From 159c129e478eed1f21f1947903dfde8bc5ffc90e Mon Sep 17 00:00:00 2001
From: Tomer Ohana <tomero@wix.com>
Date: Thu, 18 May 2023 16:56:54 +0100
Subject: [PATCH] calculate ssr stacktrace offset lazily

---
 packages/vite/src/node/ssr/ssrStacktrace.ts | 24 ++++++++++++++-------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/packages/vite/src/node/ssr/ssrStacktrace.ts b/packages/vite/src/node/ssr/ssrStacktrace.ts
index fe66b8803530b7..9cb2545263b2c3 100644
--- a/packages/vite/src/node/ssr/ssrStacktrace.ts
+++ b/packages/vite/src/node/ssr/ssrStacktrace.ts
@@ -2,20 +2,28 @@ import { TraceMap, originalPositionFor } from '@jridgewell/trace-mapping'
 import type { ModuleGraph } from '../server/moduleGraph'
 
 let offset: number
-try {
-  new Function('throw new Error(1)')()
-} catch (e) {
-  // in Node 12, stack traces account for the function wrapper.
-  // in Node 13 and later, the function wrapper adds two lines,
-  // which must be subtracted to generate a valid mapping
-  const match = /:(\d+):\d+\)$/.exec(e.stack.split('\n')[1])
-  offset = match ? +match[1] - 1 : 0
+
+function calculateOffsetOnce() {
+  if (offset !== undefined) {
+    return
+  }
+
+  try {
+    new Function('throw new Error(1)')()
+  } catch (e) {
+    // in Node 12, stack traces account for the function wrapper.
+    // in Node 13 and later, the function wrapper adds two lines,
+    // which must be subtracted to generate a valid mapping
+    const match = /:(\d+):\d+\)$/.exec(e.stack.split('\n')[1])
+    offset = match ? +match[1] - 1 : 0
+  }
 }
 
 export function ssrRewriteStacktrace(
   stack: string,
   moduleGraph: ModuleGraph,
 ): string {
+  calculateOffsetOnce()
   return stack
     .split('\n')
     .map((line) => {