$watch inside a service?

Question

Is it possible to set up a $watch on an array of objects inside a service (I\'d like the $watch declaration itself to be inside the service)?

Answer 1

Hey just had a situation where I had a pretty big watch setup on 2 different controllers.

As I didn't want to duplicate any code I just defined to function in my service :

angular
    .module('invoice')
    .factory('invoiceState', function () {
        var invoice = {
            client_info: {
                lastname: "",
                firstname: "",
                email: "",
                phone: "",
                id_client: "",
                ... 
             }
        }
        invoice.watchAccommodation = function (newVal, oldVal) {
            var accommodation = newVal;
            //Whatever you would normally have in your watch function
        }

Then I can just call this function in the watch of any controller into which I injected the service

function NewInvoiceCtrl(invoiceState) {
    $scope.$watch('invoice.accommodation',invoiceState.watchAccommodation, true);
}

I do not have much experience with AngularJS so I can't really go into the performance aspects of this approach but it works ;)