Forcing a digest in Angular

Question

At some point after a user action I would like to cause a digest to occur, so the UI reflects a change in the data-model backing it.

I have a service that performs some change in a callback (asynchronously).

I understand that $scope only makes sense in the context of a controller. Can I achieve the same effect by performing $apply() on the $rootScope?

I have seen code that checks for $$phase or similar related to avoiding digest errors, what checks should I perform in order to trigger a digest safely?

Answer 1

See this answer: Running $apply on $rootScope vs any other scope

You can call $rootScope.$apply() outside of a controller (i.e. in a service) in order to trigger a digest loop.

Alternatively, you could consider using $broadcast and $on to send a notification to other parts of your app when something needs refreshing. (See Understanding Angular’s $scope and $rootScope event system $emit, $broadcast and $on)

// in a service
$rootScope.$broadcast('myCustomEvent', {
  someProp: 'foobar'
  // other data
});

// in a controller or another service
$scope.$on('myCustomEvent', function (event, data) {
  console.log(data);
  // do something with this event
});