From 8dc810aca34b7e18181c814ee77be6bd089a0dc7 Mon Sep 17 00:00:00 2001
From: Ryan Wu <imgreenwu@gmail.com>
Date: Wed, 27 Jan 2021 22:03:46 +0800
Subject: [PATCH] fix event listener leak and also support custom scroll event

---
 src/js/aos.js | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/src/js/aos.js b/src/js/aos.js
index bcf6d5e1..5240da60 100644
--- a/src/js/aos.js
+++ b/src/js/aos.js
@@ -48,6 +48,8 @@ let options = {
 // http://browserhacks.com/#hack-e71d8692f65334173fee715c222cb805
 const isBrowserNotSupported = () => document.all && !window.atob;
 
+// current window scroll handler
+let currentScrollHandler
 const initializeScroll = function initializeScroll() {
   // Extend elements objects in $aosElements with their positions
   $aosElements = prepare($aosElements, options);
@@ -57,12 +59,17 @@ const initializeScroll = function initializeScroll() {
   /**
    * Handle scroll event to animate elements on scroll
    */
-  window.addEventListener(
-    'scroll',
-    throttle(() => {
-      handleScroll($aosElements, options.once);
-    }, options.throttleDelay)
-  );
+  const eventName = options.customScrollEvent || 'scroll'
+
+  if (currentScrollHandler) {
+    window.removeEventListener(eventName, currentScrollHandler)
+  }
+
+  currentScrollHandler = throttle((event) => {
+    handleScroll($aosElements, event)
+  }, options.throttleDelay)
+  
+  window.addEventListener(eventName, currentScrollHandler)
 
   return $aosElements;
 };