Replace unload handlers with visibilitychange (#36387)

Co-authored-by: Mathias Jakobsen <mathias.jakobsen@overleaf.com>
GitOrigin-RevId: 3b52b09445597d93eb5fdfa5a343fbc2fac14d6c

services/web/frontend/js/features/source-editor/extensions/cursor-position.ts

@@ -24,16 +24,21 @@ export const cursorPosition = ({
   return [
     // store cursor position
     ViewPlugin.define(view => {
-      const unloadListener = () => {
+      const handleVisibilityChange = () => {
+        if (document.visibilityState === 'hidden') {
           storeCursorPosition(view, docId)
         }
+      }
 
-      window.addEventListener('unload', unloadListener)
+      document.addEventListener('visibilitychange', handleVisibilityChange)
 
       return {
         destroy: () => {
-          window.removeEventListener('unload', unloadListener)
-          unloadListener()
+          document.removeEventListener(
+            'visibilitychange',
+            handleVisibilityChange
+          )
+          storeCursorPosition(view, docId)
         },
       }
     }),

services/web/frontend/js/features/source-editor/extensions/scroll-position.ts

@@ -51,13 +51,15 @@ export const scrollPosition = (
     // store/dispatch scroll position
     ViewPlugin.define(
       view => {
-        const unloadListener = () => {
+        const handleVisibilityChange = () => {
+          if (document.visibilityState === 'hidden') {
             if (lineInfo) {
               storeScrollPosition(lineInfo, view, docId)
             }
           }
+        }
 
-        window.addEventListener('unload', unloadListener)
+        document.addEventListener('visibilitychange', handleVisibilityChange)
 
         return {
           update: (update: ViewUpdate) => {
@@ -82,8 +84,13 @@ export const scrollPosition = (
           },
           destroy: () => {
             scrollHandler.cancel()
-            window.removeEventListener('unload', unloadListener)
-            unloadListener()
+            document.removeEventListener(
+              'visibilitychange',
+              handleVisibilityChange
+            )
+            if (lineInfo) {
+              storeScrollPosition(lineInfo, view, docId)
+            }
           },
         }
       },