Reactive extensions for RxSwift

ReactiveExtensions.swift

import RxCocoa
import RxSwift

// MARK: - Reactive protocol

protocol ReactiveDisposable {
    
    var disposeBag: DisposeBag { get }
}

// MARK: - Reactive extensions

extension Reactive where Base: UIScrollView {
    
    // MARK: - UIScrollView reactive extension
    
    public var reachedBottom: Observable<Void> {
        let scrollView = self.base as UIScrollView
        return self.contentOffset.flatMap{ [weak scrollView] (contentOffset) -> Observable<Void> in
            guard let scrollView = scrollView else { return Observable.empty() }
            let visibleHeight = scrollView.frame.height - self.base.contentInset.top - scrollView.contentInset.bottom
            let y = contentOffset.y + scrollView.contentInset.top
            let threshold = max(0.0, scrollView.contentSize.height - visibleHeight)
            return (y > threshold) ? Observable.just(()) : Observable.empty()
        }
    }
    
    public var startedDragging: Observable<Void> {
        let scrollView = self.base as UIScrollView
        return scrollView.panGestureRecognizer.rx
            .event
            .filter({ $0.state == .began })
            .map({ _ in () })
    }
}

extension Reactive where Base: UIViewController {
    
    // MARK: - UIViewController reactive extension
    
    public var viewDidLoad: Observable<Void> {
        return self.sentMessage(#selector(UIViewController.viewDidLoad)).map({ _ in return () })
    }
    
    public var viewWillAppear: Observable<Bool> {
        return self.sentMessage(#selector(UIViewController.viewWillAppear(_:))).map({ $0.first as! Bool })
    }
    
    public var viewDidAppear: Observable<Bool> {
        return self.sentMessage(#selector(UIViewController.viewDidAppear(_:))).map({ $0.first as! Bool })
    }
    
    public var viewWillDisappear: Observable<Bool> {
        return self.sentMessage(#selector(UIViewController.viewWillDisappear(_:))).map({ $0.first as! Bool })
    }
    
    public var viewDidDisappear: Observable<Bool> {
        return self.sentMessage(#selector(UIViewController.viewDidDisappear(_:))).map({ $0.first as! Bool })
    }
}