let string = "Hello, Swift!"
string[safe: 0..<5]  // "Hello"
string[safe: 0...4]  // "Hello"
string[safe: 0..<14] // nil

print("FF".intBaseHex)  // 255
print("0xFF".intBaseHex)  // 255

" hello world \n\t".trimmed()  // "hello world"

var string = " hello world \n\t"
string.trimming()
string  // "hello world"

" \n\t ".isBlank  // true

"".nilIfEmpty  // nil

"".isNilOrEmpty  // true
([] as? [String]).isNilOrEmpty  // true

"hello".isNone  // false
"hello".isSome  // true

var name: String? = nil
name.isNone  // true
name.isSome  // false

var name: String? = nil

name.noneDo {
    print("name is nil")
}

name.someDo {
    print("name has a value \($0)")
}

let animals = ["Zebra", "Giraffe", "Tiger"]
let zebra = animals[safe: 0] // "Zebra"
let lion = animals[safe: 3] // nil

class UserCell: UITableViewCell, NibReusable { }

tableView.register(UserCell.self)
let cell: UserCell = tableView.dequeueReusableCell(for: indexPath)

class PhotoCell: UICollectionViewCell, NibReusable { }

collectionView.register(PhotoCell.self)
let cell: PhotoCell = collectionView.dequeueReusableCell(for: indexPath)

extension UserDefaults.Name {
    static let username: UserDefaults.Name = "SwiftDevHints-Demo.Username"
    static let password: UserDefaults.Name = "SwiftDevHints-Demo.Password"
}

// Register Initial Value
UserDefaults.standard.register(defaults: [.username: "Unknown"])

// Set Value
UserDefaults.standard.set("Derek", forName: .username)
UserDefaults.standard.set("12345", forName: .password)

// Get Value
let username = UserDefaults.standard.string(forName: .username)
let password = UserDefaults.standard.string(forName: .password)

let color = UIColor(red: 255, green: 32, blue: 171)

let color = UIColor(hexString: "FF20AB") 

let color = UIColor(constrastingBlackOrWhiteColorOn: UIColor.green)

let hexString = UIColor.red.hexString // #FF0000

let rgb = UIColor.red.rgbComponents // (red: 255, green: 0, blue: 0)
let rgba = UIColor.red.rgbaComponents // (red: 1.0, green: 0.0, blue: 0.0, alpha: 1.0)
let hsba = UIColor.red.hsbaComponents // (hue: 0.0, saturation: 1.0, brightness: 1.0, alpha: 1.0)

let randomColor = UIColor.random

let bundle = Bundle.main

let displayName = bundle.displayName
let identifier = bundle.identifier
let version = bundle.version
let build = bundle.build

// All keys
private enum InfoPlistKey: String {
case name = "CFBundleName"
case displayName = "CFBundleDisplayName"
case developmentRegion = "CFBundleDevelopmentRegion"
case identifier = "CFBundleIdentifier"
case version = "CFBundleShortVersionString"
case build = "CFBundleVersion"
case packageType = "CFBundlePackageType"
}

let today = Date()                   // December 17, 2017 at 5:54:46 PM GMT+8
let startOfToday = today.startOfDay  // December 17, 2017 at 12:00:00 AM GMT+8
let endOfToday = today.endOfDay      // December 17, 2017 at 11:59:59 PM GMT+8
let previousDay = today.previousDay  // December 16, 2017 at 5:54:46 PM GMT+8
let nextDay = today.nextDay          // December 18, 2017 at 5:54:46 PM GMT+8

// December 14, 2017 at 5:54:46 PM GMT+8
// December 15, 2017 at 5:54:46 PM GMT+8
// December 16, 2017 at 5:54:46 PM GMT+8
let last3Days = today.lastDays(withCount: 3, includingToday: false)

// December 17, 2017 at 5:54:46 PM GMT+8
// December 18, 2017 at 5:54:46 PM GMT+8
// December 19, 2017 at 5:54:46 PM GMT+8
let next3Days = today.nextDays(withCount: 3, includingToday: true)