From 661a2687bc8782553a87ceaa58a84967b6077507 Mon Sep 17 00:00:00 2001
From: Gerben <gerben@treora.com>
Date: Thu, 15 Feb 2018 23:46:51 +0100
Subject: [PATCH] Listen to scroll events

---
 src/content_script.js | 28 ++++++++++++++++++----------
 1 file changed, 18 insertions(+), 10 deletions(-)

diff --git a/src/content_script.js b/src/content_script.js
index 6f3efdc..5eb6202 100644
--- a/src/content_script.js
+++ b/src/content_script.js
@@ -47,20 +47,28 @@ function hideBanners() {
 }
 
 
-function startCheckingLoop() {
+function main() {
+  let active = false
   let revert
 
-  function checkScroll() {
-    if (window.scrollY > 20 && !revert) {
-      revert = hideBanners()
-    } else if (window.scrollY <= 0 && revert) {
-      revert()
-      revert = undefined
+  function onScroll() {
+    let action
+    if (window.scrollY > 20 && !active) {
+      active = true
+      action = () => { revert = hideBanners() }
+    } else if (window.scrollY <= 0 && active) {
+      active = false
+      action = () => {
+        revert && revert()
+        revert = undefined
+      }
+    }
+    if (action) {
+      window.requestAnimationFrame(action)
     }
-    window.requestAnimationFrame(checkScroll);
   }
 
-  window.requestAnimationFrame(checkScroll);
+  window.addEventListener('scroll', onScroll)
 }
 
-startCheckingLoop();
+main()