// I return the count of watchers on the current page.
function getWatchCount() {
// Keep track of the total number of watch bindings on the page.
var total = 0;
// There are cases in which two different ng-scope markers will actually be referencing
// the same scope, such as with transclusion into an existing scope (ie, cloning a node
// and then linking it with an existing scope, not a new one). As such, we need to make
// sure that we don't double-count scopes.
var scopeIds = {};
// AngularJS denotes new scopes in the HTML markup by appending the classes "ng-scope"
// and "ng-isolate-scope" to appropriate elements. As such, rather than attempting to
// navigate the hierarchical Scope tree, we can simply query the DOM for the individual
// scopes. Then, we can pluck the watcher-count from each scope.
// --
// NOTE: Ordinarily, it would be a HUGE SIN for an AngularJS service to access the DOM
// (Document Object Model). But, in this case, we're not really building a true AngularJS
// service, so we can break the rules a bit.
angular.forEach(
document.querySelectorAll( ".ng-scope , .ng-isolate-scope" ),
countWatchersInNode
);
return( total );
// ---
// PRIVATE METHODS.
// ---
// I count the $watchers in to the scopes (regular and isolate) associated with the given
// element node, and add the count to the running total.
function countWatchersInNode( node ) {
// Get the current, wrapped element.
var element = angular.element( node );
// It seems that in earlier versions of AngularJS, the separation between the regular
// scope and the isolate scope where not as strong. The element was flagged as having
// an isolate scope (using the ng-isolate-scope class); but, there was no .isolateScope()
// method before AngularJS 1.2. As such, in earlier versions of AngularJS, we have to
// fall back to using the .scope() method for both regular and isolate scopes.
if ( element.hasClass( "ng-isolate-scope" ) && element.isolateScope ) {
countWatchersInScope( element.isolateScope() );
}
// This class denotes a non-isolate scope in later versions of AngularJS; but,
// possibly an isolate-scope in earlier versions of AngularJS (1.0.8).
if ( element.hasClass( "ng-scope" ) ) {
countWatchersInScope( element.scope() );
}
}
// I count the $$watchers in the given scope and add the count to the running total.
function countWatchersInScope( scope ) {
// Make sure we're not double-counting this scope.
if ( scopeIds.hasOwnProperty( scope.$id ) ) {
return;
}
scopeIds[ scope.$id ] = true;
// The $$watchers value starts out as NULL until the first watcher is bound. As such,
// the $$watchers collection may not exist yet on this scope.
if ( scope.$$watchers ) {
total += scope.$$watchers.length;
}
}
}