discourse/app/assets/javascripts/admin/routes/admin-customize-themes-edit.js.es6

export default Ember.Route.extend({
  model(params) {
    const all = this.modelFor('adminCustomizeThemes');
    const model = all.findBy('id', parseInt(params.theme_id));
    return model ? { model,
      target: params.target,
      field_name: params.field_name
    } : this.replaceWith('adminCustomizeThemes.index');
  },

  serialize(wrapper) {
    return {
      model: wrapper.model,
      target: wrapper.target || "common",
      field_name: wrapper.field_name || "scss",
      theme_id: wrapper.model.get("id")
    };
  },

  setupController(controller, wrapper) {
    controller.set("model", wrapper.model);
    controller.setTargetName(wrapper.target || "common");
    controller.set("fieldName", wrapper.field_name || "scss");
    this.controllerFor("adminCustomizeThemes").set("editingTheme", true);
  },

});