From 98648b83f8aa2bd5b6746597a805809e65839579 Mon Sep 17 00:00:00 2001
From: Alexander Brandon Coles <a.coles@openproject.com>
Date: Thu, 18 Jun 2026 00:11:44 +0200
Subject: [PATCH] =?UTF-8?q?=F0=9F=A4=96=20Merge=20PR=20#75138=20[hotwired?=
 =?UTF-8?q?=5F=5Fturbo]=20Fix=20morph=20attribute=20`mutationType`=20value?=
 =?UTF-8?q?s=20by=20@myabc?=
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---
 types/hotwired__turbo/hotwired__turbo-tests.ts | 7 +++++++
 types/hotwired__turbo/index.d.ts               | 2 +-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/types/hotwired__turbo/hotwired__turbo-tests.ts b/types/hotwired__turbo/hotwired__turbo-tests.ts
index 4bc74319abaabc..5e3f6a582d3f63 100644
--- a/types/hotwired__turbo/hotwired__turbo-tests.ts
+++ b/types/hotwired__turbo/hotwired__turbo-tests.ts
@@ -151,6 +151,13 @@ document.addEventListener("turbo:submit-end", function(event) {
     }
 });
 
+document.addEventListener("turbo:before-morph-attribute", function(event) {
+    // $ExpectType string
+    event.detail.attributeName;
+    // $ExpectType "update" | "remove"
+    event.detail.mutationType;
+});
+
 // Test start() function
 start();
 
diff --git a/types/hotwired__turbo/index.d.ts b/types/hotwired__turbo/index.d.ts
index bfd2d8a12449be..fa0c1ce206aec8 100644
--- a/types/hotwired__turbo/index.d.ts
+++ b/types/hotwired__turbo/index.d.ts
@@ -520,7 +520,7 @@ export type TurboMorphElementEvent = CustomEvent<{
 
 export type TurboBeforeMorphAttributeEvent = CustomEvent<{
     attributeName: string;
-    mutationType: "updated" | "removed";
+    mutationType: "update" | "remove";
 }>;
 
 export type TurboBeforeFrameMorphEvent = CustomEvent<{