ha1f

import Foundation

extension Array {
    /// Returns unique pairs from array
    /// Following is result of `[1, 2, 3, 4].pairs()`
    /// [(1, 2), (1, 3), (1, 4), (2, 3), (2, 4), (3, 4)]
    func pairs() -> [(Element, Element)] {
        return enumerated()
            .flatMap { index, element in
                dropFirst(index.advanced(by: 1))

ha1f

//
//  Zip3Sequence.swift
//
//  Created by はるふ on 2018/05/28.
//  Copyright © 2018年 ha1f. All rights reserved.
//

import Foundation

/// An iterator for `Zip3Sequence`.

ha1f

class OperationGroup<T1, T2> {
    private var item1: T1?
    private var item2: T2?
    private var observers: [(T1, T2) -> Void] = []
    
    func notify1(_ item: T1) {
        item1 = item
        _notifyIfNeeded()
    }
    

ha1f

protocol Drinkable {
}

struct 🍶: Drinkable {}
struct 🍺: Drinkable {}
struct 🍸: Drinkable {}

struct Person {
}

ha1f

import Foundation

/// Debouncer is useful for situations like following.
/// If we want to execute action n sec after the last trigger.
public final class Debouncer<T> {
    let dispatchQueue: DispatchQueue
    let interval: TimeInterval
    let action: (T) -> Void

    private var _lastDispatchTime: DispatchTime?

ha1f

//
//  UserDefaultsStoreItem.swift
//
//  Created by ha1f on 2019/02/26.
//  Copyright © 2019年 ha1f. All rights reserved.
//

import Foundation

struct UserDefaultsStoreItem<T> {

ha1f

//
//  KeyboardSizeObserver.swift
//  KeyboardFrameObserver
//
//  Created by ha1f on 2019/02/08.
//  Copyright © ha1f 2019年 ha1f. All rights reserved.
//

import UIKit

ha1f

final class DeallocNotifier {
    private var _observers: [() -> Void] = []

    func observe(_ observer: @escaping () -> Void) {
        _observers.append(observer)
    }

    deinit {
        _observers.forEach { observer in
            observer()

ha1f

//
//  CircleView.swift
//
//  Created by ha1f on 2019/02/27.
//  Copyright © 2019年 ha1f. All rights reserved.
//

import UIKit

/// I guess this is faster than using cornerRadius.

ha1f

import Foundation

struct YearMonthDay {
    var year: Int
    var month: Int
    var day: Int
    
    /// Extracts yearMonthDay from Date, using calendar.
    static func from(_ date: Date, calendar: Calendar = Calendar(identifier: .gregorian)) -> YearMonthDay {
        let components = calendar.dateComponents([.year, .month, .day], from: date)