ah - need to use toSorted so you don't mutate

Author: robotastic

frontend/src/System/ListSystems.js

@@ -49,11 +49,7 @@ const ListSystems = (props) => {
 
   let popularSystems = [];
   if (isSuccess && systems.systems) {
-    const sortedSystems = systems.systems.sort((a, b) => {
-      
-      return b.clientCount - a.clientCount;
-    });
-    popularSystems = sortedSystems.slice(0, 4);
+    popularSystems = systems.systems.toSorted((a, b) => b.clientCount - a.clientCount).slice(0, 4);
   }
   const handleContactClick = (system) => {
     setContactSystem(system);