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);
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" });