Default Dynamic Path

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle'
});

router.js

import Ember from 'ember';
import config from './config/environment';

const Router = Ember.Router.extend({
  location: 'none',
  rootURL: config.rootURL
});

Router.map(function() {
  this.route('user', {path: '/user'}, function() {
    this.route('user_by_id', {path: '/:user_id', resetNamespace: true});
  });
  this.route('user2', {path: '/user2'}, function() {
    this.route('user2_by_id', {path: '/:user_id', resetNamespace: true});
  });
});

export default Router;

routes.user.js

import Ember from 'ember';

export default Ember.Route.extend({
  model(params) {
    return (params && params.user_id) ? { name: params.user_id } : {
      name: 'Default User'
    };
  }
});

routes.user.user-by-id.js

import Ember from 'ember';

export default Ember.Route.extend({
  model(params) {
    return {
      name: params.user_id
    };
  }
});

routes.user2.js

import Ember from 'ember';

export default Ember.Route.extend({
  model(params) {
    return (params && params.user_id) ? { name: params.user_id } : {
      name: 'Default User'
    };
  }
});

routes.user2.user2-by-id.js

import Ember from 'ember';

export default Ember.Route.extend({
  model() {
    this.modelFor('user2');
  }
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{outlet}}
<br>
<br>

templates.user.hbs

{{model.name}}

templates.user2.hbs

{{model.name}}

twiddle.json

{
  "version": "0.10.6",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.9.0",
    "ember-data": "2.9.0",
    "ember-template-compiler": "2.9.0",
    "ember-testing": "2.9.0"
  },
  "addons": {}
}