discourse-cakeday/assets/javascripts/discourse/routes/build-cakeday-route.js

import DiscourseRoute from "discourse/routes/discourse";

export default (storeName, filter) => {
  return class BuildCakedayRoute extends DiscourseRoute {
    model(params) {
      if (filter) {
        params.filter = filter;
      }

      return this.store.find(storeName, params);
    }
  };
};