Failed async call in resolve

Question

I've added the following to my app.config in order to resolve a globally needed variable before allowing any of my routes to kick off their associated controller. This has been working great, however I am concerned about scenarios in which this async call falls. If that were to happen this would not resolve properly and my app would never render. How could I protect against this scenario?

var originalWhen = $routeProvider.when;

$routeProvider.when = function(path, route) {
  if (!route.resolve) {
    route.resolve = {};
  }
  angular.extend(route.resolve, {
    availableCodes: function($rootScope, serverService) {
      if ($rootScope.isAuthenticated) {
        return numbersService.getAvailableCodes().$promise.then(function(data) {
          $rootScope.availableCodes = data.codes;
        });
      }
    }
  });
  return originalWhen.call($routeProvider, path, route);
};

Answer 1

For global resolvers patching when isn't the best solution (method patching is an extreme case and should be avoided if possible), generally putting them to $routeChangeStart listener is cleaner and gives more control.

The errors should be handled in $routeChangeError, listeners get rejection reason as the fourth argument:

  var ignored = ['/resolver-error'];

  $rootScope.$on('$routeChangeStart', function (e, to) {
    if (ignored.indexOf(to.originalPath) >= 0)
      return;

    to.resolve = to.resolve || {};
    // can be overridden by route definition
    to.resolve.availableCodes = to.resolve.availableCodes || 'availableCodesService';
  });

  $rootScope.$on('$routeChangeError', function (e, to, from, reason) {
    if (reason === ...) {
      $location.path('/resolver-error');
    }
  });

This allows to skip this resolver on at least one route which is supposed to provide a feedback on resolution error.