Angularjs service to toggle own model object boolean using $interval - angularjs

Question

With the help of user3696882 I managed to set up a service:
app.service('metro', function() {
this.flagValue = {value: false};
this.setFlagValue = function(flagValue){
this.flagValue.value = flagValue;
};
this.getFlagValue = function(){
return this.flagValue;
};
});
that forms the model for a boolean that is being toggled true/false every second by one of my controllers:
function GlobalCtrl( $scope , $interval , metro ) {
var th = this;
$interval(function () {
th.pulse = !th.pulse;
metro.setFlagValue( th.pulse );
}, 1000 );
}
The toggling model in my service can show up in another part of the view - accessed by a different controller:
function ViewCtrl( $scope , metro ) {
var th = this;
th.pulse = metro.getFlagValue() ;
}
Full solution available in this Plunker
Maybe I am taking things too far, but I'd like to be able to have a service depending on $interval which toggles its own model.
I made:
app.factory('loop_toggle', ['$interval', function($interval ) {
var flagObj = {value: false};
function flip() {
flagObj.value = !flagObj.value;
}
$interval(flip, 1000);
return {
current : flagObj
};
}]);
However, with my modifed controller:
function ViewCtrl( $scope , metro , loop_toggle ) {
var th = this;
th.pulse = metro.getFlagValue() ;
th.loop = loop_toggle.current.value;
}
I cannot see anything toggling: just a static "false".
Development so far available in this Plunker
I suppose I could make do with a service metronome being toggled by a controller - but isn't that having business logic in the wrong place?

Answer 1

You need to update th.loop after each second,
Add dependaincies into ViewCtrl
ViewCtrl.$inject = ['$scope' , 'metro' , 'loop_toggle', '$interval' ] ;
Update your th.loop using $interval
function ViewCtrl( $scope , metro , loop_toggle, $interval ) {
var th = this;
th.pulse = metro.getFlagValue() ;
$interval(function () {
th.loop = loop_toggle.current.value;
}, 1000 );
}
Updated plunker
metro service doesn't need $interval, but Why loop_toggle factory needs $interval to update value?
Here are some explanations Service vs Factory