Detecting failure of push.register()

This might be trivial, but I can’t seem to figure out how to detect failure of push.register() - is there a straightforward way of doing this? I couldn’t find anything in the docs apart from the success callback (which receives the token).

Also, what would be the appropriate action on failure? Retry?

To partially answer my own question, there seems to be an onError option for the Ionic.Push object:

$ionicPlatform.ready(function() {
  var push = new Ionic.Push({
    "debug": true,
    "onError": function() {

  push.register(function(token) {
    console.log("Device token:",token.token);
    push.saveToken(token);  // persist the token in the Ionic Platform

I’m still not clear on the appropriate action for onError?