From ad9501852e658fcc9c41358f751500defb6b7f9c Mon Sep 17 00:00:00 2001
From: Yerin Park <109822768+yeriiiii@users.noreply.github.com>
Date: Wed, 19 Jun 2024 13:43:17 +0900
Subject: [PATCH] feat(anchor-positioning-composable): add attachment resizing
 observer (#221)

---
 .../src/composables/anchor-positioning-composable.ts   | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/packages/vlossom/src/composables/anchor-positioning-composable.ts b/packages/vlossom/src/composables/anchor-positioning-composable.ts
index f591e32ed..eacf6a8f0 100644
--- a/packages/vlossom/src/composables/anchor-positioning-composable.ts
+++ b/packages/vlossom/src/composables/anchor-positioning-composable.ts
@@ -100,8 +100,14 @@ export function usePositioning(anchor: Ref<HTMLElement>, attachment: Ref<HTMLEle
                 computePosition(attachInfo);
 
                 throttledComputePosition = utils.function.throttle(computePosition.bind(null, attachInfo), 30);
-                resizeObserver = new ResizeObserver(throttledComputePosition);
-                resizeObserver.observe(anchor.value);
+
+                const hasResizeObserver = window && window.ResizeObserver !== undefined;
+                if (hasResizeObserver) {
+                    resizeObserver = new ResizeObserver(throttledComputePosition);
+                    resizeObserver.observe(anchor.value);
+                    resizeObserver.observe(attachment.value);
+                }
+
                 document.addEventListener('scroll', throttledComputePosition, true);
                 window.addEventListener('resize', throttledComputePosition, true);
             } catch (error: any) {