1-traits.js

angular.module('myApp')
  .factory('Traits', function() {
      return {
          apply: function (_class, _trait) {
              _.each(_trait, function (method, name) {
                  _class.prototype[name] = method;
              });
          }
      }
  });

2-my-trait.js

angular.module('myApp')
  .factory('MyTrait', function() {
      return {
          someMethod: function (param) {
              // 
          },
          anotherMethod: function (param) {
              // 
          }
      }
  });

3-using-trait.js

angular.module('myApp')
  .factory('MyResource', function($resource, Traits, MyTrait) {
    var resource = $resource();
    Traits.apply(resource, MyTrait);

    return resource;
  });

ImplementingTraitsInAngularJS.md

Simple way how to implement Traits in AngularJS