docs: function deepFreeze(obj) {
    Object.freeze(obj);
    forEachKeyValue(obj, (name, prop) => {
      const type = typeof obj;
      if (
        prop !== null &&
        (type === 'object' || type === 'function') &&
        !Object.isFrozen(prop)
      ) {
        deepFreeze(prop);
      }
    });
    return obj;
  }