diff --git a/src/core/WakaTimeCore.ts b/src/core/WakaTimeCore.ts
index a7e1d74..f07d938 100644
--- a/src/core/WakaTimeCore.ts
+++ b/src/core/WakaTimeCore.ts
@@ -170,6 +170,7 @@ class WakaTimeCore {
         if (!contains(url, items.blacklist as string)) {
           await this.sendHeartbeat(
             {
+              branch: null,
               hostname: items.hostname as string,
               project,
               url,
@@ -189,6 +190,7 @@ class WakaTimeCore {
           await this.sendHeartbeat(
             {
               ...heartbeat,
+              branch: null,
               hostname: items.hostname as string,
               project: heartbeat.project ?? project,
             },
@@ -340,12 +342,12 @@ class WakaTimeCore {
     let userAgent;
     if (IS_FIREFOX) {
       browserName = 'firefox';
-      userAgent = navigator.userAgent.match(/Firefox\/\S+/g)![0];
+      userAgent = navigator.userAgent.match(/Firefox\/\S+/g)?.[0];
     } else if (IS_EDGE) {
       browserName = 'edge';
       userAgent = navigator.userAgent;
     } else {
-      userAgent = navigator.userAgent.match(/Chrome\/\S+/g)![0];
+      userAgent = navigator.userAgent.match(/Chrome\/\S+/g)?.[0];
     }
     const payload: Record<string, unknown> = {
       entity: heartbeat.url,