From a82d678a6be173f3235f253e36a1c65bdeaf96d8 Mon Sep 17 00:00:00 2001
From: lizarusi <liza.ru@walnut.io>
Date: Thu, 13 Aug 2026 13:40:20 +0200
Subject: [PATCH 1/2] Add failing tests: outerHTML morph of a text or comment
 oldNode throws TypeError

---
 test/core.js | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/test/core.js b/test/core.js
index 5e10210..7d559c8 100644
--- a/test/core.js
+++ b/test/core.js
@@ -121,6 +121,28 @@ describe("Core morphing tests", function () {
     );
   });
 
+  it("morphs outerHTML properly when oldNode is a text node", function () {
+    let parent = make("<div>Foo</div>");
+    let initial = parent.firstChild;
+    Idiomorph.morph(initial, "<button>Bar</button>", {
+      morphStyle: "outerHTML",
+    });
+    parent.innerHTML.should.equal("<button>Bar</button>");
+  });
+
+  it("morphs outerHTML properly when oldNode is a comment node", function () {
+    let parent = make(
+      "<div><p>Before</p><!-- placeholder --><p>After</p></div>",
+    );
+    let initial = parent.childNodes[1];
+    Idiomorph.morph(initial, "<button>Bar</button>", {
+      morphStyle: "outerHTML",
+    });
+    parent.innerHTML.should.equal(
+      "<p>Before</p><button>Bar</button><p>After</p>",
+    );
+  });
+
   it("morphs innerHTML as content properly when argument is null", function () {
     let initial = make("<div>Foo</div>");
     Idiomorph.morph(initial, null, { morphStyle: "innerHTML" });

From e68de56ebdb8095ae56bb862a7f34962cb31291b Mon Sep 17 00:00:00 2001
From: lizarusi <liza.ru@walnut.io>
Date: Thu, 13 Aug 2026 13:40:52 +0200
Subject: [PATCH 2/2] Guard findIdElements against roots without
 querySelectorAll

Morphing a text or comment node with morphStyle: "outerHTML" throws
"TypeError: root.querySelectorAll is not a function", because morph()
passes the raw oldNode into createIdMaps -> findIdElements. Guarding
with optional chaining (same pattern as the getAttribute guard below)
lets the morph proceed; the rest of the algorithm already handles
non-element nodes correctly.
---
 src/idiomorph.js | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/idiomorph.js b/src/idiomorph.js
index 257c040..ab21454 100644
--- a/src/idiomorph.js
+++ b/src/idiomorph.js
@@ -1085,7 +1085,8 @@ var Idiomorph = (function () {
      * @returns {Element[]}
      */
     function findIdElements(root) {
-      let elements = Array.from(root.querySelectorAll("[id]"));
+      // root could be a text or comment node which doesn't have `querySelectorAll`
+      let elements = Array.from(root.querySelectorAll?.("[id]") ?? []);
       // root could be a document fragment which doesn't have `getAttribute`
       if (root.getAttribute?.("id")) {
         elements.push(root);