const config = {
  db: { host: "localhost", port: 5432 },
  cache: { ttl: 300 },
};

Object.freeze(config);

config.debug = true;
config.db.port = 9999;
config.cache = { ttl: 600 };

const sealed = Object.seal({ version: "1.0", meta: { build: 42 } });

sealed.version = "2.0";
sealed.author = "devteam";
sealed.meta.build = 99;

console.log(
  config.debug,
  config.db.port,
  config.cache.ttl,
  sealed.version,
  sealed.author,
  sealed.meta.build
);