diff --git a/resources/ts/lib/recurrence.ts b/resources/ts/lib/recurrence.ts
index 6e5b278..d7c6f8c 100644
--- a/resources/ts/lib/recurrence.ts
+++ b/resources/ts/lib/recurrence.ts
@@ -22,7 +22,7 @@ export function parseCron(cron: string | null): {
             value: 0,
             date: null,
         };
-    } else if (cron.startsWith("RRULE:") || cron.startsWith("DTSTART:")) {
+    } else if (isRrule(cron)) {
         return parseRrule(cron);
     } else if ((value = /^0 (\d+) \* \* \*$/i.exec(cron)) !== null) {
         return {
@@ -75,6 +75,10 @@ export function parseCron(cron: string | null): {
     }
 }
 
+function isRrule(cron: string): boolean {
+    return cron.startsWith("RRULE:") || cron.startsWith("DTSTART:");
+}
+
 export function parseRrule(rule: string): {
     type: CronType;
     value: number;
@@ -193,7 +197,7 @@ export function nextCronReset(
         return null;
     }
     try {
-        if (cron.startsWith("RRULE:")) {
+        if (isRrule(cron)) {
             try {
                 const rule = new RRule({
                     ...RRule.parseString(cron),