browser-calls-node | sample application which shows you how to make and receive | Frontend Framework library

Twilio developer evangelist here.

From the documentation on the reject event:

.on('reject', handler())

Register a handler function to be called when the connection is rejected and Connection.status() has transitioned to closed. This is raised when Connection.reject() is called.

The reject event is only called when your Connection object rejects an incoming call. Not when an outbound call is rejected.

If you want to tell the difference between a call that was answered by the other end or not you should listen for the events ringing, and accept. If the call only goes through the ringing and disconnect events, then it was hung up on. If it is accepted then disconnected, then a connection was made.

You could also see what happened to the call in the action webhook. The DialCallStatus will tell you whether the call was completed, no-answer, busy, etc.