Set common route for the loading routes (by different levels)

routes.js

import Route from 'ember-route';

const ROUTE_LEVEL = {
  third: 3,
  fourth: 4
};

/**
 * @param app
 * @private
 */
export function initialize(app) {

  let mainRouter = app.lookup('router:main');

  mainRouter.one('willTransition', this, () => {
    let LoadingRoute = Route.extend({ templateName: 'user/loading' });
    setLoadingRoutes(LoadingRoute, ROUTE_LEVEL.third);
    setLoadingRoutes(LoadingRoute, ROUTE_LEVEL.fourth);
  });

  /**
   * @param {Route} LoadingRoute
   * @param {Number} routeLevel
   * @private
   */
  function setLoadingRoutes(LoadingRoute, routeLevel) {

    let routeNames = Object.keys(mainRouter.router.recognizer.names);

    routeNames.forEach((routeName) => {

      let segments = routeName.split('.');
      let SEGMENT_LAST_IDX = segments.length - 1;

      let isRouteLevel = _segmentLevelCheck(segments, routeLevel);

      if (isRouteLevel && segments[SEGMENT_LAST_IDX].indexOf('loading') !== -1) {
        app.register(`route:${routeName}`, LoadingRoute);
      }

    });

  }

  /**
   * Route level check
   * @param {Array} uriSegments
   * @param {Number} routeLevel
   * @returns {boolean}
   * @private
   */
  function _segmentLevelCheck(uriSegments, routeLevel) {
    return uriSegments.length === routeLevel;
  }

}

export default {
  name: 'routes',
  initialize
};