How can I debounce a method call?

Question

I\'m trying to use a UISearchView to query google places. In doing so, on text change calls for my UISearchBar, I\'m making a request to google pla

Answer 1

A couple subtle improvements on quickthyme's excellent answer:

1. Add a delay parameter, perhaps with a default value.
2. Make Debounce an enum instead of a class, so you can skip having to declare a private init.

enum Debounce {
    static func input(_ input: T, delay: TimeInterval = 0.3, current: @escaping @autoclosure () -> T, perform: @escaping (T) -> Void) {
        DispatchQueue.main.asyncAfter(deadline: .now() + delay) {
            guard input == current() else { return }
            perform(input)
        }
    }
}

It's also not necessary to explicitly declare the generic type at the call site — it can be inferred. For example, if you want to use Debounce with a UISearchController, in updateSearchResults(for:) (required method of UISearchResultsUpdating), you would do this:

func updateSearchResults(for searchController: UISearchController) {
    guard let text = searchController.searchBar.text else { return }

    Debounce.input(text, current: searchController.searchBar.text ?? "") {
        // ...
    }

}