AngularJs - cancel route change event

Question

How do I cancel route change event in AngularJs?

My current code is

$rootScope.$on("$routeChangeStart", function (event, next, current) {

// do some validation checks
if(validation checks fails){

    console.log("validation failed");

    window.history.back(); // Cancel Route Change and stay on current page  

}
});

with this even if the validation fails Angular pulls the next template and associated data and then immediately switches back to previous view/route. I don't want angular to pull next template & data if validation fails, ideally there should be no window.history.back(). I even tried event.preventDefault() but no use.

Answer

Instead of $routeChangeStart use $locationChangeStart

Here's the discussion about it from the angularjs guys: https://github.com/angular/angular.js/issues/2109

Edit 3/6/2018 You can find it in the docs: https://docs.angularjs.org/api/ng/service/$location#event-$locationChangeStart

Example:

$scope.$on('$locationChangeStart', function(event, next, current) {
    if ($scope.form.$invalid) {
       event.preventDefault();
    }
});