修复编译

lib/formatDate.js

@@ -5,6 +5,7 @@
  * @returns {string}
  */
 export default function formatDate (date, local) {
+  if (!date) return ''
   const d = new Date(date)
   const options = { year: 'numeric', month: 'short', day: 'numeric' }
   const res = d.toLocaleDateString(local, options)