http: Make OutgoingMessage more streamlike

Implement missing getters error & closed. Add support for
proper "writable" check through isWritable helper.

We cannot fix the OutgoingMessage.writable propery as that
will break the ecosystem.

Author: ronag

lib/_http_outgoing.js

@@ -45,6 +45,7 @@ const assert = require('internal/assert');
 const EE = require('events');
 const Stream = require('stream');
 const internalUtil = require('internal/util');
+const { kIsWritable } = require('internal/streams/utils');
 const { kOutHeaders, utcDate, kNeedDrain } = require('internal/http');
 const { Buffer } = require('buffer');
 const {
@@ -88,6 +89,7 @@ const kCorked = Symbol('corked');
 const kUniqueHeaders = Symbol('kUniqueHeaders');
 const kBytesWritten = Symbol('kBytesWritten');
 const kEndCalled = Symbol('kEndCalled');
+const kErrored = Symbol('errored');
 
 const nop = () => {};
 
@@ -146,11 +148,30 @@ function OutgoingMessage() {
 
   this._keepAliveTimeout = 0;
 
-  this._onPendingData = nop;
+  this[kErrored] = null;
 }
 ObjectSetPrototypeOf(OutgoingMessage.prototype, Stream.prototype);
 ObjectSetPrototypeOf(OutgoingMessage, Stream);
 
+ObjectDefineProperty(OutgoingMessage.prototype, kIsWritable, {
+  get() {
+    // TODO (ronag): w.ended?
+    return !this.destroyed && !this[kErrored] && !this.finished;
+  }
+});
+
+ObjectDefineProperty(OutgoingMessage.prototype, 'errored', {
+  get() {
+    return this[kErrored];
+  }
+});
+
+ObjectDefineProperty(OutgoingMessage.prototype, 'closed', {
+  get() {
+    return this._closed;
+  }
+});
+
 ObjectDefineProperty(OutgoingMessage.prototype, 'writableFinished', {
   __proto__: null,
   get() {
@@ -320,6 +341,8 @@ OutgoingMessage.prototype.destroy = function destroy(error) {
   }
   this.destroyed = true;
 
+  this[kErrored] = error;
+
   if (this.socket) {
     this.socket.destroy(error);
   } else {

lib/internal/streams/utils.js

@@ -9,6 +9,7 @@ const {
 const kDestroyed = Symbol('kDestroyed');
 const kIsErrored = Symbol('kIsErrored');
 const kIsReadable = Symbol('kIsReadable');
+const kIsWritable = Symbol('kIsWritable');
 const kIsDisturbed = Symbol('kIsDisturbed');
 
 function isReadableNodeStream(obj, strict = false) {
@@ -126,6 +127,7 @@ function isReadable(stream) {
 }
 
 function isWritable(stream) {
+  if (stream && stream[kIsWritable] != null) return stream[kIsWritable];
   if (typeof stream?.writable !== 'boolean') return null;
   if (isDestroyed(stream)) return false;
   return isWritableNodeStream(stream) &&
@@ -262,6 +264,7 @@ function isErrored(stream) {
 }
 
 module.exports = {
+  kIsWritable,
   kDestroyed,
   isDisturbed,
   kIsDisturbed,