ember.js - Map controller property to different query parameter key -

in emberjs documentation there 2 ways map controller property different query-param key.

controller

in controller creating object instead of string in queryparams array:

export default ember.controller.extend({   queryparams: ['page', 'filter', {     category: 'articles_category'   }],   category: null,   page: 1,   filter: 'recent' }); 

route

in route mapping alias:

export default ember.route.extend({   queryparams: {     category: {       // default, query param url key same name       // controller property name. use `as` specify       // different url key.       as: 'articles_category'     }   } } 

which 1 best way configure mapping? , why there 2 ways?