application.js

import $ from 'jquery';
import _ from 'underscore';
import Radio from 'backbone.radio';
import nprogress from 'nprogress';
import {Application} from 'backbone.marionette';

let routerChannel = Radio.channel('router');

nprogress.configure({
  showSpinner: false
});

export default Application.extend({
  initialize() {
    this.$body = $(document.body);

    this.listenTo(routerChannel, {
      'before:transition' : this.onBeforeTransition,
      'transition'        : this.onTransition,
      'transition:abort'  : this.onTransitionAbort
    });
  },

  onBeforeTransition() {
    this.transitioning = true;
    // Don't show for synchronous route changes takin more than 50ms    
    _.delay(() => {
      if (this.transitioning) {
        nprogress.start();
      }
    }, 50);
  },

  onTransition() {
    this.transitioning = false;
    this.$body.scrollTop(0);
    nprogress.done();
  },

  onTransitionAbort() {
    this.transitioning = false;
    nprogress.done(true);
  }
});