Medium blogpost snippet

CountryAutocompleteProvider.swift

import RxSwift

private let countries = ["Afghanistan", "Albania", /* all the countries */ "Zambia", "Zimbabwe"]

final class CountryAutocompleteProvider: AutocompleteProvider {

    func autocomplete(text: String) -> Observable<[Prediction]> {
        func predictionsFor(prefix: String) -> [Prediction] {
            return countries
                .flatMap { country in
                    if let matchingRange = country.range(of: prefix, options: .caseInsensitive) {
                        return Prediction(predictedText: country, matchingRange: matchingRange)
                    } else {
                        return nil
                    }
                }
        }

        return Observable.just(text)
            .map {  predictionsFor(prefix: $0) }
            .delay(0.3, scheduler: MainScheduler.instance) // 0.3 second delay to simulate network
    }
}