angularjs - Non-Singleton Services in Angular -

angular states in documentation services singletons:

angular services singletons 

counterintuitively, module.factory returns singleton instance.

given there plenty of use-cases non-singleton services, best way implement factory method return instances of service, each time exampleservice dependency declared, satisfied different instance of exampleservice?

i don't think should ever have factory return newable function begins break down dependency injection , library behave awkwardly, third parties. in short, not sure there legitimate use cases non-singleton sevices.

a better way accomplish same thing use factory api return collection of objects getter , setter methods attached them. here pseudo-code showing how using kind of service might work:

.controller( 'mainctrl', function ( $scope, widgetservice ) {   $scope.onsearchformsubmission = function () {     widgetservice.findbyid( $scope.searchbyid ).then(function ( widget ) {       // returned object, complete getter/setters       $scope.widget = widget;     });   };    $scope.onwidgetsave = function () {     // method persists widget object     $scope.widget.$save();   }; }); 

this pseudo-code looking widget id , being able save changes made record.

here's pseudo-code service:

.factory( 'widgetservice', function ( $http ) {    function widget( json ) {     angular.extend( this, json );   }    widget.prototype = {     $save: function () {       // todo: strip irrelevant fields       var scrubbedobject = //...       return $http.put( '/widgets/'+this.id, scrubbedobject );     }   };    function getwidgetbyid ( id ) {     return $http( '/widgets/'+id ).then(function ( json ) {       return new widget( json );     });   }     // public widget api   return {     // ...     findbyid: getwidgetbyid     // ...   }; }); 

though not included in example, these kinds of flexible services manage state.

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i don't have time right now, if helpful can put simple plunker later demonstrate.