A bit more fault tolerant

(e.g. when only one service is mocked)

suppliers/srv/mashup.js

@@ -37,7 +37,7 @@ module.exports = async()=>{ // called by server.js
   // Subscribe to changes in the S4 origin of Suppliers data
   S4bupa.on ('BusinessPartner.Changed', async msg => { //> would be great if we had batch events from S/4
     let replica = await SELECT.one('ID').from (Suppliers) .where ({ID: msg.data.BusinessPartner})
-    return replicate (replica.ID)
+    if (replica) return replicate (replica.ID)
   })
 
   /**