Conditionally spread prop, type must have a ‘[Symbol.iterator]()’ method that returns an iterator

I am trying to conditionally set a spread prop, if isCurrentLocation is present, but I get the error,

Type ‘RecentSearch | null’ must have a ‘Symbol.iterator’ method that returns an iterator.

Any ideas?

  const storeLatestSearch = async (searchToSave: RecentSearch) => {

    const newSearches = [
      ...(searchToSave.isCurrentLocation ? searchToSave : null),
      ...filteredSearches,
    ];

Type definition:

export type RecentSearch = {
  addressName: string;
  id: string;
  date: Date;
  fuelType: FuelType;
  searchDistance: SearchDistance;
  isCurrentLocation?: boolean;
  searchResults: SearchResult[] | undefined;
};