Using safe $apply

In the course of developing AngularJS applications, you will become very familiar with $apply() and its implications. The $apply() function cannot be invoked while the $apply() phase is already in progress without causing AngularJS to raise an exception. While in simpler applications, this problem can be solved by being careful and methodical about where you invoke $apply(); however, this becomes increasingly more difficult when applications incorporate third-party extensions with high DOM event density. The resulting problem is one where the necessity of invoking $apply is indeterminate.

As it is entirely possible to ascertain the state of the application when $apply() might need to be invoked, you can create a wrapper for $apply() to ascertain the state of the application, and conditionally invoke $apply() only when not in the $apply phase, essentially creating an idempotent $apply() method.

Tip

This recipe contains content that the AngularJS wiki considers an anti-pattern...