From dcd8f2798859f8b2ac1077f0d0bd768120f9886a Mon Sep 17 00:00:00 2001
From: Andy <andyhorng168@gmail.com>
Date: Fri, 5 Feb 2021 04:16:02 +0000
Subject: [PATCH] Handle preserved element that might not be existing

---
 src/htmx.js                    | 4 +++-
 test/attributes/hx-preserve.js | 9 +++++++++
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/htmx.js b/src/htmx.js
index 55a64ab9..01444234 100644
--- a/src/htmx.js
+++ b/src/htmx.js
@@ -479,7 +479,9 @@ return (function () {
             forEach(findAll(fragment, '[hx-preserve], [data-hx-preserve]'), function (preservedElt) {
                 var id = getAttributeValue(preservedElt, "id");
                 var oldElt = getDocument().getElementById(id);
-                preservedElt.parentNode.replaceChild(oldElt, preservedElt);
+                if (oldElt != null) {
+                    preservedElt.parentNode.replaceChild(oldElt, preservedElt);
+                }
             });
         }
 
diff --git a/test/attributes/hx-preserve.js b/test/attributes/hx-preserve.js
index 3ad01cb7..08521bc0 100644
--- a/test/attributes/hx-preserve.js
+++ b/test/attributes/hx-preserve.js
@@ -17,5 +17,14 @@ describe("hx-preserve attribute", function () {
         byId("d2").innerHTML.should.equal("New Content");
     })
 
+    it('handles preserved element that might not be existing', function () {
+        this.server.respondWith("GET", "/test", "<div id='d1' hx-preserve>New Content</div><div id='d2'>New Content</div>");
+        var div = make("<div hx-get='/test'><div id='d2'>Old Content</div></div>");
+        div.click();
+        this.server.respond();
+        byId("d1").innerHTML.should.equal("New Content");
+        byId("d2").innerHTML.should.equal("New Content");
+    })
+
 });