From 02a9f842f57e37470a6b42ce64f677a075190490 Mon Sep 17 00:00:00 2001
From: Phillip9587 <barta.phillip@gmail.com>
Date: Mon, 25 Nov 2024 23:06:34 +0100
Subject: [PATCH] refactor: remove `ServerResponse.headersSent` support check

`http.ServerResponse.headersSent` was added in v0.9.3. `http2.Http2ServerResponse.headersSent` was added in v8.4.0
---
 HISTORY.md |  1 +
 index.js   | 18 ++----------------
 2 files changed, 3 insertions(+), 16 deletions(-)

diff --git a/HISTORY.md b/HISTORY.md
index 520f4d8..0710571 100644
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -1,6 +1,7 @@
 unreleased
 ==================
 
+  * remove `ServerResponse.headersSent` support check
   * remove unnecessary devDependency `safe-buffer`
   * remove `unpipe` package and use native `unpipe()` method
   * remove unnecessary devDependency `readable-stream`
diff --git a/index.js b/index.js
index f887765..7d24afb 100644
--- a/index.js
+++ b/index.js
@@ -88,7 +88,7 @@ function finalhandler (req, res, options) {
     var status
 
     // ignore 404 on in-flight response
-    if (!err && headersSent(res)) {
+    if (!err && res.headersSent) {
       debug('cannot 404 after headers sent')
       return
     }
@@ -122,7 +122,7 @@ function finalhandler (req, res, options) {
     }
 
     // cannot actually respond
-    if (headersSent(res)) {
+    if (res.headersSent) {
       debug('cannot %d after headers sent', status)
       if (req.socket) {
         req.socket.destroy()
@@ -245,20 +245,6 @@ function getResponseStatusCode (res) {
   return status
 }
 
-/**
- * Determine if the response headers have been sent.
- *
- * @param {object} res
- * @returns {boolean}
- * @private
- */
-
-function headersSent (res) {
-  return typeof res.headersSent !== 'boolean'
-    ? Boolean(res._header)
-    : res.headersSent
-}
-
 /**
  * Send response.
  *