diff --git a/action_text-trix/app/assets/javascripts/trix.js b/action_text-trix/app/assets/javascripts/trix.js
index 8d831cd03..9e3d41a7c 100644
--- a/action_text-trix/app/assets/javascripts/trix.js
+++ b/action_text-trix/app/assets/javascripts/trix.js
@@ -1397,7 +1397,7 @@ $\
         const result = [];
         for (const key in this.values) {
           const value = this.values[key];
-          result.push(result.push(key, value));
+          result.push(key, value);
         }
         this.array = result.slice(0);
       }
diff --git a/src/test/unit/hash_test.js b/src/test/unit/hash_test.js
new file mode 100644
index 000000000..33c7e24cf
--- /dev/null
+++ b/src/test/unit/hash_test.js
@@ -0,0 +1,9 @@
+import { assert, test, testGroup } from "test/test_helper"
+
+import Hash from "trix/core/collections/hash"
+
+testGroup("Hash", () => {
+  test("toArray returns flattened key-value pairs", () => {
+    assert.deepEqual(new Hash({ a: 1, b: 2 }).toArray(), [ "a", 1, "b", 2 ])
+  })
+})
diff --git a/src/trix/core/collections/hash.js b/src/trix/core/collections/hash.js
index c5200fdf7..93c7e9082 100644
--- a/src/trix/core/collections/hash.js
+++ b/src/trix/core/collections/hash.js
@@ -80,7 +80,7 @@ export default class Hash extends TrixObject {
       const result = []
       for (const key in this.values) {
         const value = this.values[key]
-        result.push(result.push(key, value))
+        result.push(key, value)
       }
       this.array = result.slice(0)
     }