From 230d4f7724ce4b62560a21e1ab0ec022241ed3de Mon Sep 17 00:00:00 2001
From: Noeri Huisman <8823461+mrxz@users.noreply.github.com>
Date: Thu, 27 Jun 2024 21:17:11 +0200
Subject: [PATCH] Don't stringify properties with undefined values in
 flushToDOM (#5549)

---
 src/core/schema.js           |  4 +++-
 tests/core/component.test.js | 13 +++++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/src/core/schema.js b/src/core/schema.js
index 905a60b1ec4..103e211993a 100644
--- a/src/core/schema.js
+++ b/src/core/schema.js
@@ -187,7 +187,9 @@ module.exports.stringifyProperties = function (propData, schema) {
       value = stringifyProperty(propValue, propDefinition);
       if (!propDefinition) { warn('Unknown component property: ' + propName); }
     }
-    stringifiedData[propName] = value;
+    if (value !== undefined) {
+      stringifiedData[propName] = value;
+    }
   }
   return stringifiedData;
 };
diff --git a/tests/core/component.test.js b/tests/core/component.test.js
index 8331a05e078..045a59c894d 100644
--- a/tests/core/component.test.js
+++ b/tests/core/component.test.js
@@ -1149,6 +1149,19 @@ suite('Component', function () {
       el.components.dummy.flushToDOM();
       assert.equal(HTMLElement.prototype.getAttribute.call(el, 'dummy'), 'isDurrr: false');
     });
+
+    test('omits cleared properties', function () {
+      var el = document.createElement('a-entity');
+      registerComponent('dummy', {
+        schema: {name: {type: 'string'}}
+      });
+      el.setAttribute('dummy', 'name', 'John');
+      el.components.dummy.flushToDOM();
+      assert.equal(HTMLElement.prototype.getAttribute.call(el, 'dummy'), 'name: John');
+      el.setAttribute('dummy', 'name', '');
+      el.components.dummy.flushToDOM();
+      assert.equal(HTMLElement.prototype.getAttribute.call(el, 'dummy'), '');
+    });
   });
 
   suite('play', function () {