From 7caca60c5dc977a94d8272a871a84d0324a10b39 Mon Sep 17 00:00:00 2001
From: Jasper Huang <jasper@expensify.com>
Date: Wed, 2 Oct 2024 09:29:04 -0700
Subject: [PATCH] ensure that round trips do not display the duplicate waypoint
 error incorrectly

---
 src/libs/TransactionUtils/index.ts | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/libs/TransactionUtils/index.ts b/src/libs/TransactionUtils/index.ts
index 9fbed928423f..0db771eaa96b 100644
--- a/src/libs/TransactionUtils/index.ts
+++ b/src/libs/TransactionUtils/index.ts
@@ -646,7 +646,10 @@ function getValidWaypoints(waypoints: WaypointCollection | undefined, reArrangeI
     let waypointIndex = -1;
 
     return waypointValues.reduce<WaypointCollection>((acc, currentWaypoint, index) => {
-        const previousWaypoint = waypointValues.at(lastWaypointIndex);
+        // Array.at(-1) returns the last element of the array
+        // If a user does a round trip, the last waypoint will be the same as the first waypoint
+        // We want to avoid comparing them as this will result in an incorrect duplicate waypoint error.
+        const previousWaypoint = lastWaypointIndex !== -1 ? waypointValues.at(lastWaypointIndex) : undefined;
 
         // Check if the waypoint has a valid address
         if (!waypointHasValidAddress(currentWaypoint)) {