From 194af023ac9394bc9526ea694309304449db1309 Mon Sep 17 00:00:00 2001
From: Basit Chonka <baasit121@icloud.com>
Date: Wed, 6 Jul 2022 11:25:37 +0200
Subject: [PATCH 1/3] listener: use bitset to save memory

---
 lib/internal/event_target.js | 52 +++++++++++++++++++++++++++++++-----
 1 file changed, 46 insertions(+), 6 deletions(-)

diff --git a/lib/internal/event_target.js b/lib/internal/event_target.js
index bd153c972ae276..8db63700a45364 100644
--- a/lib/internal/event_target.js
+++ b/lib/internal/event_target.js
@@ -347,6 +347,13 @@ function weakListeners() {
   return { registry: weakListenersState, map: objectToWeakListenerMap };
 }
 
+const FLAG_ONCE = 1;
+const FLAG_CAPTURE = 2;
+const FLAG_PASSIVE = 4;
+const FLAG_NODE_STYLE = 8;
+const FLAG_WEAK = 16;
+const FLAG_REMOVED = 32;
+
 // The listeners for an EventTarget are maintained as a linked list.
 // Unfortunately, the way EventTarget is defined, listeners are accounted
 // using the tuple [handler,capture], and even if we don't actually make
@@ -362,13 +369,21 @@ class Listener {
       previous.next = this;
     this.previous = previous;
     this.listener = listener;
-    // TODO(benjamingr) these 4 can be 'flags' to save 3 slots
-    this.once = once;
-    this.capture = capture;
-    this.passive = passive;
-    this.isNodeStyleListener = isNodeStyleListener;
+
+    let flags = 0b0;
+    if (once) 
+      flags |= FLAG_ONCE;
+    if (capture) 
+      flags |= FLAG_CAPTURE;
+    if (passive)
+      flags |= FLAG_PASSIVE;
+    if (isNodeStyleListener)
+      flags |= FLAG_NODE_STYLE;
+    if (Boolean(weak))
+      flags |= FLAG_WEAK;
+    this.flags = flags;
+
     this.removed = false;
-    this.weak = Boolean(weak); // Don't retain the object
 
     if (this.weak) {
       this.callback = new SafeWeakRef(listener);
@@ -388,6 +403,31 @@ class Listener {
     }
   }
 
+  get once() {
+    return Boolean(this.flags & FLAG_ONCE);
+  }
+  get capture() {
+    return Boolean(this.flags & FLAG_CAPTURE);
+  }
+  get passive() {
+    return Boolean(this.flags & FLAG_PASSIVE);
+  }
+  get isNodeEventTarget() {
+    return Boolean(this.flags & FLAG_NODE_STYLE);
+  }
+  get weak() {
+    return Boolean(this.flags & FLAG_WEAK);
+  }
+  get removed() {
+    return Boolean(this.flags & FLAG_REMOVED);
+  }
+  set removed(value) {
+    if (value)
+      this.flags |= FLAG_REMOVED;
+    else
+      this.flags &= ~FLAG_REMOVED;
+  }
+
   same(listener, capture) {
     const myListener = this.weak ? this.listener.deref() : this.listener;
     return myListener === listener && this.capture === capture;

From e344b4b31fe4e0960884182dfbb03686c62f91a9 Mon Sep 17 00:00:00 2001
From: Basit Chonka <baasit121@icloud.com>
Date: Wed, 6 Jul 2022 13:49:23 +0200
Subject: [PATCH 2/3] events: code styles and use bit shifts

---
 lib/internal/event_target.js | 44 ++++++++++++++++++------------------
 1 file changed, 22 insertions(+), 22 deletions(-)

diff --git a/lib/internal/event_target.js b/lib/internal/event_target.js
index 8db63700a45364..ea26771291ed2d 100644
--- a/lib/internal/event_target.js
+++ b/lib/internal/event_target.js
@@ -347,12 +347,12 @@ function weakListeners() {
   return { registry: weakListenersState, map: objectToWeakListenerMap };
 }
 
-const FLAG_ONCE = 1;
-const FLAG_CAPTURE = 2;
-const FLAG_PASSIVE = 4;
-const FLAG_NODE_STYLE = 8;
-const FLAG_WEAK = 16;
-const FLAG_REMOVED = 32;
+const kFlagOnce = 1 << 0;
+const kFlagCapture = 1 << 1;
+const kFlagPassive = 1 << 2;
+const kFlagNodeStyle = 1 << 3;
+const kFlagWeak = 1 << 4;
+const kFlagRemoved = 1 << 5;
 
 // The listeners for an EventTarget are maintained as a linked list.
 // Unfortunately, the way EventTarget is defined, listeners are accounted
@@ -371,16 +371,16 @@ class Listener {
     this.listener = listener;
 
     let flags = 0b0;
-    if (once) 
-      flags |= FLAG_ONCE;
-    if (capture) 
-      flags |= FLAG_CAPTURE;
+    if (once)
+      flags |= kFlagOnce;
+    if (capture)
+      flags |= kFlagCapture;
     if (passive)
-      flags |= FLAG_PASSIVE;
+      flags |= kFlagPassive;
     if (isNodeStyleListener)
-      flags |= FLAG_NODE_STYLE;
-    if (Boolean(weak))
-      flags |= FLAG_WEAK;
+      flags |= kFlagNodeStyle;
+    if (weak)
+      flags |= kFlagWeak;
     this.flags = flags;
 
     this.removed = false;
@@ -404,28 +404,28 @@ class Listener {
   }
 
   get once() {
-    return Boolean(this.flags & FLAG_ONCE);
+    return Boolean(this.flags & kFlagOnce);
   }
   get capture() {
-    return Boolean(this.flags & FLAG_CAPTURE);
+    return Boolean(this.flags & kFlagCapture);
   }
   get passive() {
-    return Boolean(this.flags & FLAG_PASSIVE);
+    return Boolean(this.flags & kFlagPassive);
   }
   get isNodeEventTarget() {
-    return Boolean(this.flags & FLAG_NODE_STYLE);
+    return Boolean(this.flags & kFlagNodeStyle);
   }
   get weak() {
-    return Boolean(this.flags & FLAG_WEAK);
+    return Boolean(this.flags & kFlagWeak);
   }
   get removed() {
-    return Boolean(this.flags & FLAG_REMOVED);
+    return Boolean(this.flags & kFlagRemoved);
   }
   set removed(value) {
     if (value)
-      this.flags |= FLAG_REMOVED;
+      this.flags |= kFlagRemoved;
     else
-      this.flags &= ~FLAG_REMOVED;
+      this.flags &= ~kFlagRemoved;
   }
 
   same(listener, capture) {

From 73a689eb0ba22e0d8d4b9d1424cd5b2b9ec33abf Mon Sep 17 00:00:00 2001
From: Basit <1305718+mabaasit@users.noreply.github.com>
Date: Fri, 8 Jul 2022 12:44:05 +0200
Subject: [PATCH 3/3] Update lib/internal/event_target.js

fix typo

Co-authored-by: Anna Henningsen <github@addaleax.net>
---
 lib/internal/event_target.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/internal/event_target.js b/lib/internal/event_target.js
index ea26771291ed2d..458bb9a624ac73 100644
--- a/lib/internal/event_target.js
+++ b/lib/internal/event_target.js
@@ -412,7 +412,7 @@ class Listener {
   get passive() {
     return Boolean(this.flags & kFlagPassive);
   }
-  get isNodeEventTarget() {
+  get isNodeStyleListener() {
     return Boolean(this.flags & kFlagNodeStyle);
   }
   get weak() {