code: function merge(obj1, obj2) {
    if (obj1 == null && obj2 == null) {
      return null;
    }
    const merged = { ...obj1 };
    for (const prop in obj2) {
      if (obj2[prop] != null) {
        merged[prop] = obj2[prop];
      }
    }
    return merged;
  }
docs: Merges two objects ignoring null/undefined.