NBWatcherCount.js

(function () { 
    var root = angular.element(document.querySelectorAll("body"));

    var totalWatchers = [];

    //通过data()方法找到DOM对应的$scope, 轮询所有子$scope的$$watchers数量
    var calcWatcher = function (element) {
        angular.forEach(['$scope', '$isolateScope'], function (scope) { 
            if (element.data() && element.data().hasOwnProperty(scope)) {
                angular.forEach(element.data()[scope].$$watchers, function (watcher) {
                    totalWatchers.push(watcher);
                });
            }
        });

        angular.forEach(element.children(), function (childElement) {
            calcWatcher(angular.element(childElement));
        });
    };

    calcWatcher(root);

    // Remove duplicate watchers
    var watchersWithoutDuplicates = [];
    angular.forEach(totalWatchers, function(item) {
        if(watchersWithoutDuplicates.indexOf(item) < 0) {
             watchersWithoutDuplicates.push(item);
        }
    });
    
    console.log('Total $$watcher is')
    console.log(watchersWithoutDuplicates.length);
})();