nmdias/DefaultsKit

简体中文

DefaultsKit leverages Swift 4's powerful Codable capabilities to provide a Simple and Strongly Typed wrapper on top of UserDefaults. It uses less than 70 lines of code to acomplish this.

Installation >> instructions <<

Usage

Instantiate, or get a shared instance of Defaults

let defaults = Defaults() // or Defaults.shared

Then:

// Define a key
let key = Key<String>("someKey")

// Set a value
defaults.set("Codable FTW 😃", for: key)

// Read the value back
defaults.get(for: key) // Output: Codable FTW 😃

Check if a key has a value:

if defaults.has(key) { 
    // Do your thing
}

If you just need to know that a key/value pair exists, without actually using the value, use the has() method instead of the optional get(for:key). For complex objects it will prevent any unnecessary deserialization.

Implicit Member Expression

You can find a convenience wrapper for your keys by extending DefaultsKey. This allows you use Implicit Member Expression:

// Extend with a custom key
extension DefaultsKey {
    static let someKey = Key<String>("someKey")
}

// Then use it like this
defaults.set("Some key", for: .someKey)
defaults.get(for: .someKey) // Output: Some key

Complex objects

To store a complex object just conform to the Codable protocol:

struct Person: Codable {
    let name: String
    let age: Int
}

Then:

// Create a key
let key = Key<Person>("personKey")

// Get an instance of your Codable conforming enum, struct or class
let person = Person(name: "Bonnie Greenwell", age: 80)

// Set the value
defaults.set(person, for: key)

And finally:

// Read it back
let person = defaults.get(for: key)
person?.name // Bonnie Greenwell
person?.age  // 80

Nested Objects

You can also use nested objects as long as they conform to the Codable protocol:

enum Pet: String, Codable {
    case cat
    case dog
}

struct Person: Codable {
    let name: String
    let pets: [Pet]
}

// Get a Codable conforming instante
let person = Person(name: "Claire", pets: [.cat])

// Set the value
defaults.set(person, for: key)

// And read it back
let person = defaults.get(for: key)
person?.name        // Claire
person?.pets.first  // cat

License

DefaultsKit is released under the MIT license. See LICENSE for details.

Help Wanted

Review/Translate README.zh-CN.md to Chinese

Chinese is the #1 spoken language in the world and I'd love to have DefaultsKit be more inclusive, unfortunately I don't speak Chinese. If you know chinese, and would like to help out, please see issue #1

Thank you 🙏

nmdias / DefaultsKit