From 52243d859be457ba26c1fb58a3e33e15a2eaebc6 Mon Sep 17 00:00:00 2001
From: Dimitris Sotirakis <dimitrios.sotirakis@grafana.com>
Date: Wed, 14 Apr 2021 12:47:30 +0300
Subject: [PATCH] Fix alert frequency check (#32974)

---
 public/app/features/alerting/AlertTabCtrl.ts | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/public/app/features/alerting/AlertTabCtrl.ts b/public/app/features/alerting/AlertTabCtrl.ts
index 0cd209d1473..4500758209e 100644
--- a/public/app/features/alerting/AlertTabCtrl.ts
+++ b/public/app/features/alerting/AlertTabCtrl.ts
@@ -266,7 +266,11 @@ export class AlertTabCtrl {
   checkFrequency() {
     this.frequencyWarning = '';
 
-    if (!(this.alert.frequency || '').match(/^\d+([dhms])$/)) {
+    if (!this.alert.frequency) {
+      return;
+    }
+
+    if (!this.alert.frequency.match(/^\d+([dhms])$/)) {
       this.frequencyWarning =
         'Invalid frequency, has to be numeric followed by one of the following units: "d, h, m, s"';
       return;