From ef311ddbec9e50e032cfce062bd6c69aed5ae977 Mon Sep 17 00:00:00 2001
From: Raymond Hill <rhill@raymondhill.net>
Date: Sun, 12 Nov 2023 10:35:28 -0500
Subject: [PATCH] Add ability to trigger cookie removal on specific events

As discussed with filter list volunteers.

Related discussion:
https://github.com/uBlockOrigin/uBlock-discussions/discussions/834
---
 assets/resources/scriptlets.js | 33 +++++++++++++++++++++++----------
 1 file changed, 23 insertions(+), 10 deletions(-)

diff --git a/assets/resources/scriptlets.js b/assets/resources/scriptlets.js
index e162932e7..319ef5625 100644
--- a/assets/resources/scriptlets.js
+++ b/assets/resources/scriptlets.js
@@ -2703,17 +2703,25 @@ function cookieRemover(
     if ( typeof needle !== 'string' ) { return; }
     const safe = safeSelf();
     const reName = safe.patternToRegex(needle);
-    const removeCookie = function() {
+    const extraArgs = safe.getExtraArgs(Array.from(arguments), 1);
+    const throttle = (fn, ms = 1000) => {
+        if ( throttle.timer !== undefined ) { return; }
+        throttle.timer = setTimeout(( ) => {
+            throttle.timer = undefined;
+            fn();
+        }, ms);
+    };
+    const removeCookie = ( ) => {
         document.cookie.split(';').forEach(cookieStr => {
-            let pos = cookieStr.indexOf('=');
+            const pos = cookieStr.indexOf('=');
             if ( pos === -1 ) { return; }
-            let cookieName = cookieStr.slice(0, pos).trim();
-            if ( !reName.test(cookieName) ) { return; }
-            let part1 = cookieName + '=';
-            let part2a = '; domain=' + document.location.hostname;
-            let part2b = '; domain=.' + document.location.hostname;
+            const cookieName = cookieStr.slice(0, pos).trim();
+            if ( reName.test(cookieName) === false ) { return; }
+            const part1 = cookieName + '=';
+            const part2a = '; domain=' + document.location.hostname;
+            const part2b = '; domain=.' + document.location.hostname;
             let part2c, part2d;
-            let domain = document.domain;
+            const domain = document.domain;
             if ( domain ) {
                 if ( domain !== document.location.hostname ) {
                     part2c = '; domain=.' + domain;
@@ -2722,8 +2730,8 @@ function cookieRemover(
                     part2d = '; domain=' + domain.replace('www', '');
                 }
             }
-            let part3 = '; path=/';
-            let part4 = '; Max-Age=-1000; expires=Thu, 01 Jan 1970 00:00:00 GMT';
+            const part3 = '; path=/';
+            const part4 = '; Max-Age=-1000; expires=Thu, 01 Jan 1970 00:00:00 GMT';
             document.cookie = part1 + part4;
             document.cookie = part1 + part2a + part4;
             document.cookie = part1 + part2b + part4;
@@ -2738,6 +2746,11 @@ function cookieRemover(
             }
         });
     };
+    if ( extraArgs.when === 'scroll' ) {
+        document.addEventListener('scroll', ( ) => {
+            throttle(removeCookie);
+        }, { passive: true });
+    }
     removeCookie();
     window.addEventListener('beforeunload', removeCookie);
 }