RxSwift rate limiter

ObservableType+RateLimit.swift

import RxSwift

extension ObservableType {
    
    func rateLimit(rate: NSTimeInterval) -> Observable<E> {
        let scheduler = MainScheduler.sharedInstance
        var lastEmit = NSDate()
        return filter { _ in
            return scheduler.now.timeIntervalSinceDate(lastEmit) > rate
        }
        .doOn(onNext: { _ in
            lastEmit = scheduler.now
        })
    }
}


// Sample usage
locationManager.rx_didUpdateLocations.map {$0.first}.filter{$0 != nil}.map{$0!.coordinate}.shareReplay(1)
            .rateLimit(10)
            .subscribeNext { location in
                // location once every 10 seconds at the maximum
})

Observeable<E> needs to be replaced by Observeable<Element> now.