code: function getView(app, viewName, defaultView='error'){
      /*
       * views could be an array...
       */
      let views = app.get('views');
      const ext = app.get('view engine');
  
      if(!Array.isArray(views)) views = [views];
  
      let view;
      for(var i = 0; i < views.length; i++){
          view = path.join(views[i], viewName + '.' + ext);
          if (exists(view)) return view;
      }
  
      if (app.parent) return getView(app.parent, viewName, defaultView);
  
      return defaultView;
  }
docs: This function will try to return a valid path to
  a view.
  
  It will recursively call itself while the provided
  express instance has a `parent` attribute.
  
  @TODO: Move to it's own package.
  
  @param  {Object} app                   Express instance
  @param  {String} viewName              View name without ext
  @param  {String} [defaultView='error']
  @return {String}                       Path to a valid view.