diff --git a/debug.js b/debug.js
index 2a90045..69903d5 100644
--- a/debug.js
+++ b/debug.js
@@ -10,12 +10,17 @@ function prettyDOM(htmlElement, maxLength, options) {
     htmlElement = htmlElement.documentElement;
   }
 
-  const debugContent = prettyFormat(htmlElement, {
-    plugins: [DOMElement, DOMCollection],
-    printFunctionName: false,
-    highlight: true,
-    ...options
-  });
+  const debugContent = prettyFormat(
+    htmlElement,
+    Object.assign(
+      {
+        plugins: [DOMElement, DOMCollection],
+        printFunctionName: false,
+        highlight: true
+      },
+      options
+    )
+  );
   return maxLength !== undefined && htmlElement.outerHTML.length > maxLength
     ? `${debugContent.slice(0, maxLength)}...`
     : debugContent;