propertyWrapperCollection

A collection of tested Swift Property Wrappers.

List

@Clamping
@CopyOnWrite
@DynamicColor
@UserDefault
@LateInitialized
@Logged
@Rounded
@UnitInterval
@Trimmed
@Default

Requirements

Xcode 11 & Swift 5

@Clamping

A property wrapper that automatically clamps its wrapped value in a range.

@Clamping(1.0...14.0) var pH : Double = 7.0
pH = 0
print(pH) //1
ph = 20
print(ph) //14

@CopyOnWrite

A property wrapper that if object is referenced by other object, the object will .copy() as new same type object.

class Texture:NSObject,NSCopying {
    func copy(with zone: NSZone? = nil) -> Any {
        let copy = Texture()
        return copy
    }
}
    
@CopyOnWrite var texture: Texture = .init()

@DynamicColor

A property wrapper arround UIColor to support dark mode.

By default in iOS >= 13 it uses the new system wide user interface style trait and dynamic UIColor constructor to support dark mode without any extra effort. On prior iOS versions it defaults to light.

@DynamicColor(lightVariant: .black, darkVariant: .white)
    var dynamicColor: UIColor

// The color will automatically update when traits change
view.backgroundColor = backgroundColor

@UserDefault

A type safe property wrapper to set and get values from UserDefaults with support for defaults values.

@UserDefault("has_seen_app_introduction", defaultValue: false)
static var hasSeenAppIntroduction: Bool

@LateInitialized

A property wrapper that implement Swift Implicitly Unwrapped Optional, if Access it before initializing will result in fatal error

@LateInitialized var text:String
print(text) //fatalError("value has not yet been set!")
//

@Logged

A property wrapper that when you set value ,will print its value

@Logged var param:String = ""
param = "newText"
//print newText in debug mode

//in Swift 5.5  add "Extend Property Wrappers to Function and Closure parameters" new function , that means you can put  Property Wrappers before function parameter

class Test{
    func runAnimation(@Logged withDuration duration: Double) {
        
    }
}
// duration paramter will print when call runAnimation

@Rounded

A property wrapper that rounds the double to decimal places value

@Rounded(digits: 2) var number: Double = 3.1415926
print(number)   //3.14

@Rounded(digits: 3) var number: Double = 3.1415926
print(number)   //3.142

@Rounded(digits: 4) var number: Double = 3.1415926
print(number)   //3.1416

@UnitInterval

A property wrapper that automatically clamps its wrapped value in 0...1

struct RGB {
    @UnitInterval var red: Double
    @UnitInterval var green: Double
    @UnitInterval var blue: Double
}

let cornflowerBlue = RGB(red: 0.392, green: 0.584, blue: 0.929)

@Trimmed

A wrapper that automatically trims strings both on initialization and reassignment.

@Trimmed
var text = " \n Hello, World! \n\n    "

print(text) // "Hello, World!"

// By default trims white spaces and new lines, but it also supports any character set
@Trimmed(characterSet: .whitespaces)
var text = " \n Hello, World! \n\n    "
print(text) // "\n Hello, World! \n\n"

@Default

A property wrapper when decode support for defaults values.

struct Demo:Decodable {
   @Default<String> var text:String
   @Default<Bool> var check:Bool
   @Default<Int> var count1:Int
}

let json = #"{"count1": 12345, "text": "My First Video", "check": true}"#
let value = try! JSONDecoder().decode(Demo.self, from: json.data(using: .utf8)!)
print(value)
//value.count1 12345
//value.text  "My First Video"
//value.check  true

let json = #"{"check": true}"#
let value = try! JSONDecoder().decode(Demo.self, from: json.data(using: .utf8)!)
print(value)
//value.count1 0
//value.text  ""

kingnight / propertyWrapperCollection