AngularJS 1 on before print directive

onBeforePrint.js

/**
 * AngularJS example directive. 
 * Allows you to modify the page DOM and CSS styles before printing by exexuting the passed expression. 
 * Will force a $digest phase before the print operation.
 * 
 * Example: <div ng-class="{printed: isPrinted}" on-before-print="printed = true" />
 */
module.directive('onBeforePrint', ['$window', '$rootScope', '$timeout', function onBeforePrint($window, $rootScope, $timeout) {
	var beforePrintDirty = false;
	var listeners = [];

	var beforePrint = function() {
		if (beforePrintDirty) return;

		beforePrintDirty = true;				

		if (listeners) {
			for (var i = 0, len = listeners.length; i < len; i++) {
				listeners[i].triggerHandler('beforePrint');
			}

			var scopePhase = $rootScope.$$phase;

			// This must be synchronious so we call digest here.
			if (scopePhase != '$apply' && scopePhase != '$digest') {
				$rootScope.$digest();
			}
		}

		$timeout(function() {
			// This is used for Webkit. For some reason this gets called twice there.
			beforePrintDirty = false;
		}, 100, false);
	};

	if ($window.matchMedia) {
		var mediaQueryList = $window.matchMedia('print');
		mediaQueryList.addListener(function(mql) {
			if (mql.matches) {
				beforePrint();
			}
		});
	}

	$window.onbeforeprint = beforePrint;

	return function(scope, iElement, iAttrs) {
		function onBeforePrint() {
			scope.$eval(iAttrs.onBeforePrint);
		}

		listeners.push(iElement);
		iElement.on('beforePrint', onBeforePrint);

		scope.$on('$destroy', function() {
			iElement.off('beforePrint', onBeforePrint);

			var pos = -1;

			for (var i = 0, len = listeners.length; i < len; i++) {
				var currentElement = listeners[i];

				if (currentElement === iElement) {
					pos = i;
					break;
				}
			}

			if (pos >= 0) {
				listeners.splice(pos, 1);
			}
		});
	};
}])