From 0e0fa605d109cc91e08a1ae1cc560ea240fe631b Mon Sep 17 00:00:00 2001
From: Martin Trapp <94928215+martrapp@users.noreply.github.com>
Date: Wed, 16 Aug 2023 22:38:18 +0200
Subject: [PATCH] Fix 8083 (#8105)

* override wrong positions in browser history

* Lost events are taken into account during throttling
---
 .changeset/popular-planes-cover.md              |  5 +++++
 packages/astro/components/ViewTransitions.astro | 15 +++++++++++++--
 2 files changed, 18 insertions(+), 2 deletions(-)
 create mode 100644 .changeset/popular-planes-cover.md

diff --git a/.changeset/popular-planes-cover.md b/.changeset/popular-planes-cover.md
new file mode 100644
index 000000000000..c379a7edc030
--- /dev/null
+++ b/.changeset/popular-planes-cover.md
@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+ViewTransition: bug fix for lost scroll position in browser history
diff --git a/packages/astro/components/ViewTransitions.astro b/packages/astro/components/ViewTransitions.astro
index 28a17a09d743..47eb3c112765 100644
--- a/packages/astro/components/ViewTransitions.astro
+++ b/packages/astro/components/ViewTransitions.astro
@@ -38,12 +38,21 @@ const { fallback = 'animate' } = Astro.props as Props;
 
 	const throttle = (cb: (...args: any[]) => any, delay: number) => {
 		let wait = false;
+		// During the waiting time additional events are lost.
+		// So repeat the callback at the end if we have swallowed events.
+		let onceMore = false;
 		return (...args: any[]) => {
-			if (wait) return;
-
+			if (wait) {
+				onceMore = true;
+				return;
+			}
 			cb(...args);
 			wait = true;
 			setTimeout(() => {
+				if (onceMore) {
+					onceMore = false;
+					cb(...args);
+				}
 				wait = false;
 			}, delay);
 		};
@@ -163,6 +172,8 @@ const { fallback = 'animate' } = Astro.props as Props;
 			}
 			if (state?.scrollY != null) {
 				scrollTo(0, state.scrollY);
+				// Overwrite erroneous updates by the scroll handler during transition
+				persistState(state);
 			}
 
 			triggerEvent('astro:beforeload');