# Podfile
use_frameworks!

target 'YOUR_TARGET_NAME' do
    pod 'RxSwift',    '~> 3.0'
    pod 'RxCocoa',    '~> 3.0'
end

# RxTests and RxBlocking make the most sense in the context of unit/integration tests
target 'YOUR_TESTING_TARGET' do
    pod 'RxBlocking', '~> 3.0'
    pod 'RxTest',     '~> 3.0'
end ---
$ pod install

github "ReactiveX/RxSwift" ~> 3.0 ---
$ carthage update

import PackageDescription

let package = Package(
    name: "RxTestProject",
    targets: [],
    dependencies: [
        .Package(url: "https://github.com/ReactiveX/RxSwift.git", majorVersion: 3)
    ]
) ---
$ swift build

import RxCocoa
import RxSwift

searchBar.rx.text // Observable property thanks to RxCocoa
    .orEmpty // Make it non-optional
    .subscribe(onNext: { [unowned self] query in // Here we subscribe to every new value, that is not empty (thanks to filter above).
        self.shownCities = self.allCities.filter { $0.hasPrefix(query) } // We now do our "API Request" to find cities.
        self.tableView.reloadData() // And reload table view data.
})
    .addDisposableTo(disposeBag)

.debounce(0.5, scheduler: MainScheduler.instance) // Wait 0.5 for changes.
.distinctUntilChanged() // If they didn't occur, check if the new value is the same as old.
.filter { !$0.isEmpty } // If the new value is really new, filter for non-empty query.