discourse/app/assets/javascripts/admin/addon/routes/admin-config-with-settings-route.js

import { action } from "@ember/object";
import { service } from "@ember/service";
import DiscourseRoute from "discourse/routes/discourse";

export default class AdminConfigWithSettingsRoute extends DiscourseRoute {
  @service siteSettingChangeTracker;

  resetController(controller, isExiting) {
    // Have to do this because this is the parent route. We don't want to have
    // to make a controller for every single settings route when we can reset
    // the filter here.
    const settingsController = this.controllerFor(
      `${this.fullRouteName}.settings`
    );
    if (isExiting) {
      settingsController.set("filter", "");
    }
  }

  @action
  async willTransition(transition) {
    if (this.siteSettingChangeTracker.hasUnsavedChanges) {
      transition.abort();

      await this.siteSettingChangeTracker.confirmTransition();

      transition.retry();
    }
  }
}