diff --git a/src/utils/index.ts b/src/utils/index.ts
new file mode 100644
index 00000000..bb2d7740
--- /dev/null
+++ b/src/utils/index.ts
@@ -0,0 +1,5 @@
+export * from './popper'
+
+export function classNames (...classes: any[string]) {
+  return classes.filter(Boolean).join(' ')
+}