diff --git a/assets/controllers/booking_controller.js b/assets/controllers/booking_controller.js
index 5ce0c6f..274b622 100644
--- a/assets/controllers/booking_controller.js
+++ b/assets/controllers/booking_controller.js
@@ -21,9 +21,9 @@ export default class extends Controller {
     availabilitiesValueChanged(availabilities) {
         this.fieldTargets.forEach((field) => {
             let id = field.value
-            if (false === field.checked && 0 >= availabilities[id].available) {
+            if (availabilities[id] && false === field.checked && 0 >= availabilities[id].available) {
                 field.disabled = true
             }
         })
     }
-}
\ No newline at end of file
+}