diff --git a/src/inbox.ts b/src/inbox.ts
index 50646be..dad33f7 100644
--- a/src/inbox.ts
+++ b/src/inbox.ts
@@ -7,7 +7,7 @@ import { send } from "./request";
 export default async function inbox(activity:any) {
   const date = new Date()
   // get the main recipients ([...new Set()] is to dedupe)
-  const recipientList = [...new Set(idsFromValue(activity.to).concat(idsFromValue(activity.cc)).concat(idsFromValue(activity.audience)))]
+  const recipientList = [...new Set([...idsFromValue(activity.to), ...idsFromValue(activity.cc), ...idsFromValue(activity.audience)])]
 
   // if my list of followers in the list of recipients, then forward to them as well
   if(recipientList.includes(ACTOR + "/followers")) {
diff --git a/src/outbox.ts b/src/outbox.ts
index acd25b7..cdeccb8 100644
--- a/src/outbox.ts
+++ b/src/outbox.ts
@@ -35,9 +35,9 @@ export default async function outbox(activity:any):Promise<Response> {
   }
 
   // get the main recipients ([...new Set()] is to dedupe)
-  const recipientList = [...new Set(idsFromValue(activity.to).concat(idsFromValue(activity.cc)).concat(idsFromValue(activity.audience)))]
+  const recipientList = [...new Set([...idsFromValue(activity.to), ...idsFromValue(activity.cc), ...idsFromValue(activity.audience)])]
   // add in the blind recipients 
-  const finalRecipientList = [...new Set(recipientList.concat(idsFromValue(activity.bto)).concat(idsFromValue(activity.bcc)))]
+  const finalRecipientList = [...new Set([...recipientList, ...idsFromValue(activity.bto), ...idsFromValue(activity.bcc)])]
   // remove the blind recipients from the activity
   delete activity.bto
   delete activity.bcc