http: merge chunks during chunked encoding

lib/_http_outgoing.js

@@ -866,6 +866,7 @@ function strictContentLength(msg) {
   );
 }
 
+let chunkBuffer = Buffer.alloc(0);
 function write_(msg, chunk, encoding, callback, fromEnd) {
   if (typeof callback !== 'function')
     callback = nop;
@@ -930,11 +931,8 @@ function write_(msg, chunk, encoding, callback, fromEnd) {
 
   let ret;
   if (msg.chunkedEncoding && chunk.length !== 0) {
-    len ??= typeof chunk === 'string' ? Buffer.byteLength(chunk, encoding) : chunk.byteLength;
-    msg._send(NumberPrototypeToString(len, 16), 'latin1', null);
-    msg._send(crlf_buf, null, null);
-    msg._send(chunk, encoding, null, len);
-    ret = msg._send(crlf_buf, null, callback);
+    chunkBuffer = Buffer.concat([chunkBuffer, Buffer.from(chunk)]);
+    ret = true;
   } else {
     ret = msg._send(chunk, encoding, callback, len);
   }
@@ -1046,6 +1044,14 @@ OutgoingMessage.prototype.end = function end(chunk, encoding, callback) {
     throw new ERR_HTTP_CONTENT_LENGTH_MISMATCH(this[kBytesWritten], this._contentLength);
   }
 
+  if (!this._headerSent && Buffer.byteLength(chunkBuffer)) {
+    this._send(NumberPrototypeToString(Buffer.byteLength(chunkBuffer), 16), 'latin1', null);
+    this._send(crlf_buf, null, null);
+    this._send(chunkBuffer, null, null);
+    this._send(crlf_buf, null, callback);
+    chunkBuffer = Buffer.alloc(0)
+  }
+
   const finish = onFinish.bind(undefined, this);
 
   if (this._hasBody && this.chunkedEncoding) {
@@ -1062,7 +1068,6 @@ OutgoingMessage.prototype.end = function end(chunk, encoding, callback) {
     this.socket.uncork();
   }
   this[kCorked] = 0;
-
   this.finished = true;
 
   // There is the first message on the outgoing queue, and we've sent

test/own/test-http-outgoing-message.js

@@ -0,0 +1,33 @@
+/*
+In the first line of the test file you should
+enable strict mode, unless you test something
+that needs it disabled
+*/
+'use strict';
+
+/*
+the common package gives you some commonly
+used testing methods, like mustCall
+*/
+const common = require('../common');
+
+/*
+a small description on what you are testing
+*/
+// This test ensures that the http-parser can handle UTF-8 characters
+// in the http header.
+
+const assert = require('assert');
+const http = require('http');
+
+/*
+the body of the actual test - tests should exit with code 0 on success
+*/
+const server = http.createServer(
+  common.mustCall((request, response) => {
+    response.write('hello world');
+    response.end();
+  })
+);
+
+server.listen(3000, () => {});