diff --git a/js/lcn/utils.js b/js/lcn/utils.js
index 465a490e..a8b2771b 100644
--- a/js/lcn/utils.js
+++ b/js/lcn/utils.js
@@ -8,8 +8,7 @@ const assert = {
         if (actual !== expected) {
             const err = new Error(`Assertion Failed. ${message}`)
             err.data = { actual, expected}
-            // Seems like there's no such thing as captureStackTrace in firefox?
-            //Error.captureStackTrace(err, assert.equal)
+            Error.captureStackTrace?.(err, assert.equal)
             debugger
             throw err
         }
@@ -18,7 +17,7 @@ const assert = {
         if (!actual) {
             const err = new Error(`Assertion Failed. ${message}`)
             err.data = { actual }
-            // Error.captureStackTrace(err, assert.ok)
+            Error.captureStackTrace?.(err, assert.ok)
             debugger
             throw err
         }