From bc1ac57af96075f506a0f6515fd6ab4046b938f6 Mon Sep 17 00:00:00 2001
From: Paul Cento <paul.cento@gmail.com>
Date: Wed, 11 Jan 2023 14:04:24 -0500
Subject: [PATCH 1/4] Element.ShadowRoot returns an error when ShadowRoots
 slice is empty

---
 element.go | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/element.go b/element.go
index f6d6e684..f5920682 100644
--- a/element.go
+++ b/element.go
@@ -17,6 +17,10 @@ import (
 	"github.com/go-rod/rod/lib/utils"
 )
 
+var (
+	ErrNoShadowRoot = errors.New("element has no shadow root")
+)
+
 // Element implements these interfaces
 var _ proto.Client = &Element{}
 var _ proto.Contextable = &Element{}
@@ -402,6 +406,9 @@ func (el *Element) ShadowRoot() (*Element, error) {
 	}
 
 	// though now it's an array, w3c changed the spec of it to be a single.
+	if len(node.ShadowRoots) == 0 {
+		return nil, ErrNoShadowRoot
+	}
 	id := node.ShadowRoots[0].BackendNodeID
 
 	shadowNode, err := proto.DOMResolveNode{BackendNodeID: id}.Call(el)

From 384b638bd16b2c0afed51027fa4d4628d6283558 Mon Sep 17 00:00:00 2001
From: Paul Cento <paul.cento@gmail.com>
Date: Wed, 11 Jan 2023 14:24:33 -0500
Subject: [PATCH 2/4] comment exported ErrNoShadowRoot

---
 element.go | 1 +
 1 file changed, 1 insertion(+)

diff --git a/element.go b/element.go
index f5920682..420e32c5 100644
--- a/element.go
+++ b/element.go
@@ -18,6 +18,7 @@ import (
 )
 
 var (
+	// ErrNoShadowRoot is calling ShadowRoot on an Element with no shadow root
 	ErrNoShadowRoot = errors.New("element has no shadow root")
 )
 

From 618facbab14c116e87e257751615f095b0f850c7 Mon Sep 17 00:00:00 2001
From: Paul Cento <paul.cento@gmail.com>
Date: Thu, 12 Jan 2023 12:06:07 -0500
Subject: [PATCH 3/4] unit test shadow root error

---
 element.go      |  7 +------
 element_test.go |  4 ++++
 error.go        | 13 +++++++++++++
 3 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/element.go b/element.go
index 420e32c5..7d1e7da0 100644
--- a/element.go
+++ b/element.go
@@ -17,11 +17,6 @@ import (
 	"github.com/go-rod/rod/lib/utils"
 )
 
-var (
-	// ErrNoShadowRoot is calling ShadowRoot on an Element with no shadow root
-	ErrNoShadowRoot = errors.New("element has no shadow root")
-)
-
 // Element implements these interfaces
 var _ proto.Client = &Element{}
 var _ proto.Contextable = &Element{}
@@ -408,7 +403,7 @@ func (el *Element) ShadowRoot() (*Element, error) {
 
 	// though now it's an array, w3c changed the spec of it to be a single.
 	if len(node.ShadowRoots) == 0 {
-		return nil, ErrNoShadowRoot
+		return nil, &ErrNoShadowRoot{el}
 	}
 	id := node.ShadowRoots[0].BackendNodeID
 
diff --git a/element_test.go b/element_test.go
index d560eec0..6cd28d89 100644
--- a/element_test.go
+++ b/element_test.go
@@ -284,6 +284,10 @@ func TestShadowDOM(t *testing.T) {
 		g.mc.stubErr(1, proto.DOMResolveNode{})
 		el.MustShadowRoot()
 	})
+
+	elNoShadow := p.MustElement("script")
+	_, err := elNoShadow.ShadowRoot()
+	g.True((&rod.ErrNoShadowRoot{}).Is(err))
 }
 
 func TestInputTime(t *testing.T) {
diff --git a/error.go b/error.go
index 400e0f1a..ec926551 100644
--- a/error.go
+++ b/error.go
@@ -181,3 +181,16 @@ type ErrPageNotFound struct {
 func (e *ErrPageNotFound) Error() string {
 	return "cannot find page"
 }
+
+// ErrNoShadowRoot error
+type ErrNoShadowRoot struct {
+	*Element
+}
+
+// Error ...
+func (e *ErrNoShadowRoot) Error() string {
+	return fmt.Sprintf("element has no shadow root: %s", e.String())
+}
+
+// Is interface
+func (e *ErrNoShadowRoot) Is(err error) bool { _, ok := err.(*ErrNoShadowRoot); return ok }

From 9fb3b5df2fa1622876b06566def1ad4043200456 Mon Sep 17 00:00:00 2001
From: Paul Cento <paul.cento@gmail.com>
Date: Fri, 13 Jan 2023 17:32:35 -0500
Subject: [PATCH 4/4] test shadow root error contains correct error message

---
 element_test.go | 1 +
 1 file changed, 1 insertion(+)

diff --git a/element_test.go b/element_test.go
index 6cd28d89..7dff62bd 100644
--- a/element_test.go
+++ b/element_test.go
@@ -288,6 +288,7 @@ func TestShadowDOM(t *testing.T) {
 	elNoShadow := p.MustElement("script")
 	_, err := elNoShadow.ShadowRoot()
 	g.True((&rod.ErrNoShadowRoot{}).Is(err))
+	g.Has(err.Error(), "element has no shadow root:")
 }
 
 func TestInputTime(t *testing.T) {