title: Running $apply on $rootScope vs any other scope
body: <p>The <code>$apply</code> function can run on any scope, including <code>$rootScope</code>.</p>
  
  <p>Are there cases when it makes a difference if I run it on my local scope or if I run it on my <code>$rootScope</code>?</p>
  
  <p>I'm asking because I'd like to create a helper function that wraps a given function in an <code>$apply</code>.  To do that I'd always need to pass in a scope, which is A) annoying and B) not easy because I don't necessarily have a local scope.</p>
  
  <p>I'd like to always have my helper function call <code>$apply</code> on the <code>$rootScope</code>, but not if there's some risk in doing that.</p>