SwiftyUserDefaults

Modern Swift API for NSUserDefaults

SwiftyUserDefaults makes user defaults enjoyable to use by combining expressive Swifty API with the benefits of static typing. Define your keys in one place, use value types easily, and get extra safety and convenient compile-time checks for free.

Read Statically-typed NSUserDefaults for more information about this project.
Read documentation for stable version 3.0.1
Read migration guide from version 3.x to 4.x

Version 4 - alpha 1

Features • Usage • Codable • NSCoding • RawRepresentable • Default values • Custom types • Installation

Features

There's only two steps to using SwiftyUserDefaults:

Step 1: Define your keys

extension DefaultsKeys {
    static let username = DefaultsKey<String?>("username")
    static let launchCount = DefaultsKey<Int>("launchCount")
}

Step 2: Just use it!

// Get and set user defaults easily
let username = Defaults[.username]
Defaults[.hotkeyEnabled] = true

// Modify value types in place
Defaults[.launchCount] += 1
Defaults[.volume] -= 0.1
Defaults[.strings] += "… can easily be extended!"

// Use and modify typed arrays
Defaults[.libraries].append("SwiftyUserDefaults")
Defaults[.libraries][0] += " 2.0"

// Easily work with custom serialized types
Defaults[.color] = NSColor.white
Defaults[.color]?.whiteComponent // => 1.0

The convenient dot syntax is only available if you define your keys by extending magic DefaultsKeys class. You can also just pass the DefaultsKey value in square brackets, or use a more traditional string-based API. How? Keep reading.

Usage

Define your keys

To get the most out of SwiftyUserDefaults, define your user defaults keys ahead of time:

let colorKey = DefaultsKey<String>("color")

Just create a DefaultsKey object, put the type of the value you want to store in angle brackets, the key name in parentheses, and you're good to go.

You can now use the Defaults shortcut to access those values:

Defaults[colorKey] = "red"
Defaults[colorKey] // => "red", typed as String

The compiler won't let you set a wrong value type, and fetching conveniently returns String.

Take shortcuts

For extra convenience, define your keys by extending magic DefaultsKeys class and adding static properties:

extension DefaultsKeys {
    static let username = DefaultsKey<String?>("username")
    static let launchCount = DefaultsKey<Int>("launchCount")
}

And use the shortcut dot syntax:

Defaults[.username] = "joe"
Defaults[.launchCount]

Just use it!

You can easily modify value types (strings, numbers, array) in place, as if you were working with a plain old dictionary:

// Modify value types in place
Defaults[.launchCount] += 1
Defaults[.volume] -= 0.1
Defaults[.strings] += "… can easily be extended!"

// Use and modify typed arrays
Defaults[.libraries].append("SwiftyUserDefaults")
Defaults[.libraries][0] += " 2.0"

// Easily work with custom serialized types
Defaults[.color] = NSColor.white
Defaults[.color]?.whiteComponent // => 1.0

Supported types

SwiftyUserDefaults supports all of the standard NSUserDefaults types, like strings, numbers, booleans, arrays and dictionaries.

Here's a full table of built-in single value defaults:

Optional variant	Non-optional variant	Default value
String?	String	""
Int?	Int	0
Double?	Double	0.0
Bool?	Bool	false
Data?	Data	Data()
Date?	n/a	n/a
URL?	n/a	n/a

and arrays:

Array type	Optional variant
[String]	[String]?
[Int]	[Int]?
[Double]	[Double]?
[Bool]	[Bool]?
[Data]	[Data]?
[Date]	[Date]?
[URL]	[URL]?

But that's not all!

Codable

Since version 4, SwiftyUserDefaults support Codable! Just add DefaultsSerializable type to your type, like:

final class FrogCodable: Codable, DefaultsSerializable {
    let name: String
 }

No implementation needed! By doing this you will get an option to specify an optional DefaultsKey:

let frog = DefaultsKey<FrogCodable?>("frog")

Additionally, you've got an array support for free:

let froggies = DefaultsKey<[FrogCodable]?>("froggies")

NSCoding

NSCoding was supported before version 4, but in this version we take the support on another level. No need for custom subscripts anymore! Support your custom NSCoding type the same way as you can support Codable types: add DefaultsSerializable to your implemented protocols:

final class FrogSerializable: NSObject, NSCoding, DefaultsSerializable { ... }

No implementation needed as well! By doing this you will get an option to specify an optional DefaultsKey:

let frog = DefaultsKey<FrogSerializable?>("frog")

Additionally, you've got an array support also for free:

let froggies = DefaultsKey<[FrogSerializable]?>("froggies")

RawRepresentable

And the last but not least, RawRepresentable support! It's all the same situation like with NSCoding or with Codable, add one little protocol to rule them all!

enum BestFroggiesEnum: String, DefaultsSerializable {
    case Andy
    case Dandy
}

No implementation needed as well! By doing this you will get an option to specify an optional DefaultsKey:

let frog = DefaultsKey<BestFroggiesEnum?>("frog")

Additionally, you've got an array support also for free:

let froggies = DefaultsKey<[BestFroggiesEnum]?>("froggies")

Default values

Since version 4, you can support a default value for your key (arrays as well!):

let frog = DefaultsKey<FrogCodable>("frog", defaultValue: FrogCodable(name: "Froggy"))
let frogs = DefaultsKey<FrogCodable>("frogs", defaultValue: [FrogCodable(name: "Froggy")])

or you can specify a default value for the whole type using two protocols, DefaultsDefaultValueType for a single value default:

extension FrogCodable: DefaultsDefaultValueType {
   static let defaultValue: FrogCodable = FrogCodable(name: "Froggy")
}

or DefaultsDefaultArrayValueType for an array of type default:

extension FrogCodable: DefaultsDefaultArrayValueType {
   static let defaultArrayValue: [FrogCodable] = []
}

And then you can create your keys without specyfing a defaultValue each time!

let frog = DefaultsKey<FrogCodable>("frog")
let frogs = DefaultsKey<FrogCodable>("frogs")

Custom types

So let's say there is a type that is not supported yet (like NSCoding, Codable or RawRepresentable before) and you want to support it. You can do it by specializing getters and setters of DefaultsSerializable. See this extension we have for the Foundation's URL type:

extension URL: DefaultsSerializable {
    public static func get(key: String, userDefaults: UserDefaults) -> URL? {
        return userDefaults.url(forKey: key)
    }

    public static func getArray(key: String, userDefaults: UserDefaults) -> [URL]? {
        return userDefaults.data(forKey: key).flatMap(NSKeyedUnarchiver.unarchiveObject) as? [URL]
    }

    public static func save(key: String, value: URL?, userDefaults: UserDefaults) {
        userDefaults.set(value, forKey: key)
    }

    public static func saveArray(key: String, value: [URL], userDefaults: UserDefaults) {
        userDefaults.set(NSKeyedArchiver.archivedData(withRootObject: value), forKey: key)
    }
}

And if you feel there is a type that we could support this, don't hesitate and create an Issue, or better yet, make a Pull Request 😉 We're gonna try to help you as much as possible!

Remove all keys

To reset user defaults, use removeAll method.

Defaults.removeAll()

Shared user defaults

If you're sharing your user defaults between different apps or an app and its extensions, you can use SwiftyUserDefaults by overriding the Defaults shortcut with your own. Just add in your app:

var Defaults = UserDefaults(suiteName: "com.my.app")!

Installation

CocoaPods

If you're using CocoaPods, just add this line to your Podfile:

pod 'SwiftyUserDefaults', '4.0.0-alpha.1'

Install by running this command in your terminal:

pod install

Then import the library in all files where you use it:

import SwiftyUserDefaults

Carthage

Just add to your Cartfile:

github "radex/SwiftyUserDefaults" "4.0.0-alpha.1"

Swift Package Manager

Just add to your Package.swift under dependencies:

let package = Package(
    name: "MyPackage",
    products: [...],
    dependencies: [
        .package(url: "https://github.com/radex/SwiftyUserDefaults.git", .exact("4.0.0-alpha.1")),
    ],
    targets: [...]
)

More like this

If you like SwiftyUserDefaults, check out SwiftyTimer, which applies the same swifty approach to NSTimer.

You might also be interested in my blog posts which explain the design process behind those libraries:

• Swifty APIs: NSUserDefaults
• Statically-typed NSUserDefaults
• Swifty APIs: NSTimer
• Swifty methods

Contributing

If you have comments, complaints or ideas for improvements, feel free to open an issue or a pull request.

Author and license

Maintainer: Łukasz Mróz

• github.com/sunshinejr
• twitter.com/thesunshinejr
• sunshinejr.com

Created by: Radek Pietruszewski

• github.com/radex
• twitter.com/radexp
• radex.io
• [email protected]

SwiftyUserDefaults is available under the MIT license. See the LICENSE file for more info.