examples/cms-sitecore-xmcloud/scripts/config/plugins/fallback.ts

import { ConfigPlugin, JssConfig } from "..";

/**
 * This config will set fallback values for properties that were left empty
 * If neither env, nor other places had a proper value, this will ensure a fallback is set
 */
class FallbackPlugin implements ConfigPlugin {
  // should always come last
  order = 100;

  async exec(config: JssConfig) {
    return Object.assign({}, config, {
      defaultLanguage: config.defaultLanguage || "en",
      sitecoreApiKey: config.sitecoreApiKey || "no-api-key-set",
    });
  }
}

export const fallbackPlugin = new FallbackPlugin();