Swift table view and search controller didSelectRowAt index out of range - swift

Question

In Swift, I'm using SearchController and TableView with search API below.
https://developers.giphy.com/docs/api/endpoint#search
api.giphy.com/v1/gifs/search
When I input to SearchController field, TableView normally reloaded(autocompleted search keywords appear). But when I select row of TableView, 'Index out of range' error(in my ViewModel) occurred in some situation and I can't figure out what is cause.
Error occurred line
func searchKeyword(indexPath: Int) -> String? in ViewModel
This is my code.
ViewController
extension ViewController: UITableViewDataSource {
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
guard let count = self.viewModel?.resultsCount() else { return 0 }
return count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
guard let cell = searchTableView.dequeueReusableCell(withIdentifier: "CellID", for: indexPath) as? searchTableViewCell else { return UITableViewCell() }
guard let result = self.viewModel?.selectedKeyword(at: indexPath.row) else { return UITableViewCell() }
cell.configureCell(result: result.name)
return cell
}
}
extension ViewController: UISearchResultsUpdating {
func updateSearchResults(for searchController: UISearchController) {
guard let text = searchController.searchBar.text?.lowercased() else { return }
self.viewModel?.fetchKeywords(searchKeyword: text)
self.searchTableView.reloadData()
}
}
extension ViewController: UITableViewDelegate {
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
guard let nextViewController = self.storyboard?.instantiateViewController(withIdentifier: "NextViewControllerID") as? NextViewController else { return }
guard let result = self.viewModel?.searchKeyword(indexPath: indexPath.row) else { return }
nextViewController.showNextViewController(with: NextViewModel(keyword: result))
self.navigationController?.pushViewController(nextViewController.show, animated: true)
}
}
extension ViewController: UISearchResultsUpdating {
func updateResults(for searchController: UISearchController) {
guard let text = searchController.searchBar.text?.lowercased() else { return }
self.viewModel?.fetchKeywords(searchKeyword: text)
self.searchResults.reloadData()
}
}
ViewModel
func fetchKeywords(searchKeyword: String) {
self.useCase.fetchKeywords(searchKeyword: searchKeyword, paginationCount: 5) { error, result in
if let error = error {
self.error = error
}
if let result = result {
self.results = result.searchKeywords
}
}
}
func resultsCount() -> Int {
guard let count = self.results?.count else { return 0 }
return count
}
// Fatal error: Index out of range
func searchKeyword(indexPath: Int) -> String? {
guard let results = results else { return nil }
return results[indexPath].name
}
func selectedKeyword(at indexPath: Int) -> Keyword? {
guard let results = self.results else { return nil }
return results[indexPath]
}