skip generating cert each time

packages/next/src/lib/mkcert.ts

@@ -1,8 +1,9 @@
-import fs from 'fs'
-import path from 'path'
+import fs from 'node:fs'
+import path from 'node:path'
+import { X509Certificate, createPublicKey } from 'node:crypto'
 import { getCacheDirectory } from './helpers/get-cache-directory'
 import * as Log from '../build/output/log'
-import { execSync } from 'child_process'
+import { execSync } from 'node:child_process'
 const { WritableStream } = require('node:stream/web') as {
   WritableStream: typeof global.WritableStream
 }
@@ -112,6 +113,22 @@ export async function createSelfSignedCertificate(
     const keyPath = path.resolve(resolvedCertDir, 'localhost-key.pem')
     const certPath = path.resolve(resolvedCertDir, 'localhost.pem')
 
+    if (host && fs.existsSync(keyPath) && fs.existsSync(certPath)) {
+      const cert = new X509Certificate(fs.readFileSync(certPath))
+      const key = fs.readFileSync(keyPath)
+
+      if (cert.checkHost(host) && cert.checkPrivateKey(createPublicKey(key))) {
+        Log.info('Using already generated self signed certificate')
+        const caLocation = execSync(`"${binaryPath}" -CAROOT`).toString().trim()
+
+        return {
+          key: keyPath,
+          cert: certPath,
+          rootCA: `${caLocation}/rootCA.pem`,
+        }
+      }
+    }
+
     Log.info(
       'Attempting to generate self signed certificate. This may prompt for your password'
     )