detect system theme, toast performance opt.

frontend/src/hooks/toast.ts

@@ -3,17 +3,17 @@ import { useRecoilState } from 'recoil'
 import { toastListState } from '../atoms/toast'
 
 export const useToast = () => {
-  const [toasts, setToasts] = useRecoilState(toastListState)
+  const [, setToasts] = useRecoilState(toastListState)
 
   return {
     pushMessage: (message: string, severity?: AlertColor) => {
-      setToasts([{
+      setToasts(state => [...state, {
         open: true,
         message: message,
         severity: severity,
         autoClose: true,
         createdAt: Date.now()
-      }, ...toasts])
+      }])
     }
   }
 }