ignore invites that are already in use

Author: appinteractive

server/services/users/hooks/invite-code.js

@@ -18,10 +18,14 @@ module.exports = function (options = {}) { // eslint-disable-line no-unused-vars
       }
       const inviteRes = await hook.app.service('invites').find(query);
       // throw an error if the invite code does not match the one from the invite
-      if (!inviteRes.data.length) {
+      if (inviteRes.data.length !== 1) {
         throw new errors.Forbidden('invite code is invalid');
       }
 
+      if (inviteRes.data[0].wasUsed) {
+        throw new errors.Forbidden('invite already used');
+      }
+
       // set some user data from the invite like batches and roles
       hook.data.wasInvited = true;
       hook.data.inviteId = inviteRes.data[0]._id;