open-nomad/ui/app/routes/application.js

import { inject as service } from '@ember/service';
import { next } from '@ember/runloop';
import Route from '@ember/routing/route';
import { AbortError } from 'ember-data/adapters/errors';
import RSVP from 'rsvp';

export default Route.extend({
  config: service(),
  system: service(),
  store: service(),

  queryParams: {
    region: {
      refreshModel: true,
    },
  },

  resetController(controller, isExiting) {
    if (isExiting) {
      controller.set('error', null);
    }
  },

  beforeModel(transition) {
    return RSVP.all([this.get('system.regions'), this.get('system.defaultRegion')]).then(
      promises => {
        if (!this.get('system.shouldShowRegions')) return promises;

        const queryParam = transition.to.queryParams.region;
        const defaultRegion = this.get('system.defaultRegion.region');
        const currentRegion = this.get('system.activeRegion') || defaultRegion;

        // Only reset the store if the region actually changed
        if (
          (queryParam && queryParam !== currentRegion) ||
          (!queryParam && currentRegion !== defaultRegion)
        ) {
          this.system.reset();
          this.store.unloadAll();
        }

        this.set('system.activeRegion', queryParam || defaultRegion);

        return promises;
      }
    );
  },

  // Model is being used as a way to transfer the provided region
  // query param to update the controller state.
  model(params) {
    return params.region;
  },

  setupController(controller, model) {
    const queryParam = model;

    if (queryParam === this.get('system.defaultRegion.region')) {
      next(() => {
        controller.set('region', null);
      });
    }

    return this._super(...arguments);
  },

  actions: {
    didTransition() {
      if (!this.get('config.isTest')) {
        window.scrollTo(0, 0);
      }
    },

    willTransition() {
      this.controllerFor('application').set('error', null);
    },

    error(error) {
      if (!(error instanceof AbortError)) {
        this.controllerFor('application').set('error', error);
      }
    },
  },
});