diff --git a/packages/tailwindcss-class-names/src/index.js b/packages/tailwindcss-class-names/src/index.js
index 06f1b8a8f5868debc09d80300af13061bb1f618f..f9f39c4c9e30d741c28f7e84e2e10fc642f46f89 100644
--- a/packages/tailwindcss-class-names/src/index.js
+++ b/packages/tailwindcss-class-names/src/index.js
@@ -32,7 +32,10 @@   })
 }
 
 function arraysEqual(arr1, arr2) {
-  return JSON.stringify(arr1.sort()) === JSON.stringify(arr2.sort())
+  return (
+    JSON.stringify(arr1.concat([]).sort()) ===
+    JSON.stringify(arr2.concat([]).sort())
+  )
 }
 
 export default async function getClassNames(