From 2b05d7e1edef635e6c80cb383b10ea0a89279f41 Mon Sep 17 00:00:00 2001
From: Aaron Moat <2937187+AaronMoat@users.noreply.github.com>
Date: Tue, 8 Apr 2025 19:49:47 +1000
Subject: [PATCH 1/2] Fix incorrect `style="undefined;"` output in some Mermaid
 diagrams

---
 .changeset/gold-shoes-camp.md                                | 5 +++++
 .../mermaid/src/rendering-util/rendering-elements/edges.js   | 2 +-
 2 files changed, 6 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/gold-shoes-camp.md

diff --git a/.changeset/gold-shoes-camp.md b/.changeset/gold-shoes-camp.md
new file mode 100644
index 000000000..77ff7309b
--- /dev/null
+++ b/.changeset/gold-shoes-camp.md
@@ -0,0 +1,5 @@
+---
+'mermaid': patch
+---
+
+Fix incorrect `style="undefined;"` output in some Mermaid diagrams
diff --git a/packages/mermaid/src/rendering-util/rendering-elements/edges.js b/packages/mermaid/src/rendering-util/rendering-elements/edges.js
index 434c53856..ce4244ff2 100644
--- a/packages/mermaid/src/rendering-util/rendering-elements/edges.js
+++ b/packages/mermaid/src/rendering-util/rendering-elements/edges.js
@@ -562,7 +562,7 @@ export const insertEdge = function (elem, edge, clusterDb, diagramType, startNod
   }
   let svgPath;
   let linePath = lineFunction(lineData);
-  const edgeStyles = Array.isArray(edge.style) ? edge.style : [edge.style];
+  const edgeStyles = Array.isArray(edge.style) ? edge.style : edge.style ? [edge.style] : [];
   let strokeColor = edgeStyles.find((style) => style?.startsWith('stroke:'));
 
   if (edge.look === 'handDrawn') {

From d25770ee738fc9704bae37ca09ebc8d4fbd1b65c Mon Sep 17 00:00:00 2001
From: Aaron Moat <2937187+AaronMoat@users.noreply.github.com>
Date: Tue, 8 Apr 2025 19:55:05 +1000
Subject: [PATCH 2/2] Format changeset message

---
 .changeset/gold-shoes-camp.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.changeset/gold-shoes-camp.md b/.changeset/gold-shoes-camp.md
index 77ff7309b..3018e7381 100644
--- a/.changeset/gold-shoes-camp.md
+++ b/.changeset/gold-shoes-camp.md
@@ -2,4 +2,4 @@
 'mermaid': patch
 ---
 
-Fix incorrect `style="undefined;"` output in some Mermaid diagrams
+fix: Remove incorrect `style="undefined;"` attributes in some Mermaid diagrams