Deferred funcs calls for Swift

Debouncer.swift

//
//  Debouncer.swift
//
//  Created by Kirill Budevich on 11/14/19.
//  Copyright © 2019 KB. All rights reserved.
//

import Foundation

final public class Debouncer {
    private weak var timer: Timer?
    public var delay: Measurement<UnitDuration>

    public init(delay: Measurement<UnitDuration>) {
        self.delay = delay
    }

    public func debounce(block: @escaping () -> Void) {
        timer?.invalidate()
        let interval = delay.converted(to: .seconds).value
        timer = Timer.scheduledTimer(withTimeInterval: interval, repeats: false, block: { _ in block() })
    }
}

Throttler.swift

//
//  Throttler.swift
//
//  Created by Kirill Budevich on 11/14/19.
//  Copyright © 2019 KB. All rights reserved.
//

import Foundation

final public class Throttler {
    private let queue: DispatchQueue = DispatchQueue.global(qos: .background)
    private var job: DispatchWorkItem = DispatchWorkItem(block: {})
    private var previousRun: Date = Date.distantPast

    public var maxInterval: Measurement<UnitDuration>

    public init(maxInterval: Measurement<UnitDuration>) {
        self.maxInterval = maxInterval
    }

    public func throttle(block: @escaping () -> Void) {
        job.cancel()
        job = DispatchWorkItem(){ [weak self] in
            self?.previousRun = Date()
            block()
        }
        let interval = maxInterval.converted(to: .seconds).value
        let delay = Date().timeIntervalSince(previousRun) > interval ? 0 : interval
        queue.asyncAfter(deadline: .now() + Double(delay), execute: job)
    }
}