Pauses all the children's $$watchers if the expression on the attribute evaluates to true, on false it restores any backed up $$watchers http://stackoverflow.com/a/29840248/411284

pauseChildrenWatchersIf.directive.js

app.directive('pauseChildrenWatchersIf', function(){
    return {
        link: function (scope, element, attrs) {

            scope.$watch(attrs.pauseChildrenWatchersIf, function (newVal) {
                if (newVal === undefined) {
                    return;
                }
                if (newVal) {
                    toggleChildrenWatchers(element, true)
                } else {
                    toggleChildrenWatchers(element, false)
                }
            });
            function toggleChildrenWatchers(element, pause) {
                angular.forEach(element.children(), function (childElement) {
                    toggleAllWatchers(angular.element(childElement), pause);
                });
            }

            function toggleAllWatchers(element, pause) {
                var data = element.data();
                if (data.hasOwnProperty('$scope') && data.$scope.hasOwnProperty('$$watchers') && data.$scope.$$watchers) {
                    if (pause) {
                        data._bk_$$watchers = [];
                        $.each(data.$scope.$$watchers, function (i, watcher) {
                            data._bk_$$watchers.push($.extend(true, {}, watcher))
                        });

                        data.$scope.$$watchers = [];
                    } else {
                        if (data.hasOwnProperty('_bk_$$watchers')) {
                            $.each(data._bk_$$watchers, function (i, watcher) {
                                data.$scope.$$watchers.push($.extend(true, {}, watcher))
                            });
                        }
                    }

                }
                toggleChildrenWatchers(element, pause);
            }
        }
    }
});