Q:

Angular reusable functions

I have several directives that need to call the same function after doing their thing. This function needs to access the main controller scope, but also modify the DOM. How and where should this function be declared?

A:

You should use a service, services has access to $rootScope, although is it better to keep DOM modification at directive level, in certain cases you can go for it.
angular.module("myModule", [])
.factory("MyService", function ($rootScope) {
    return {
        myFunction: function () { // do stuff here }
    }
})
.directive("MyDirective", function (MyService) {
    return {
        link: function (scope, iElement, iAttrs) {
            // try do keep dom modification here, you have access to MyService,
            // let it do the algorithm and try to keep dom modification here.
            // PS: you can also inject $rootScope to directives.
        };
    };
});

