Himotoki (紐解き) is a type-safe JSON decoding library purely written in Swift. This library is highly inspired by popular JSON parsing libraries in Swift: Argo and ObjectMapper.

Himotoki has the same meaning of 'decoding' in Japanese.

• Just do JSON decoding (deserialization) well. JSON encoding (serialization) would not be supported going forward. 😉
• Much simpler API.
• Fail-fast conditional model building. This is useful for some structs with non-optional let properties.
• No external dependencies.

See a simple example from a test code:

struct Group: Decodable {
    let name: String
    let floor: Int
    let locationName: String
    let optional: [String]?

    // MARK: Decodable

    static func decode(e: Extractor) throws -> Group {
        return try Group(
            name: e <| "name",
            floor: e <| "floor",
            locationName: e <| [ "location", "name" ], // Parse nested objects
            optional: e <||? "optional" // Parse optional arrays of values
        )
    }
}

func testGroup() {
    var JSON: [String: AnyObject] = [ "name": "Himotoki", "floor": 12 ]
    
    let g = try? Group.decodeValue(JSON)
    XCTAssert(g != nil)
    XCTAssert(g?.name == "Himotoki")
    XCTAssert(g?.floor == 12)
    XCTAssert(g?.optional == nil)

    JSON["name"] = nil
    do {
        try Group.decodeValue(JSON)
    } catch let DecodeError.MissingKeyPath(keyPath) {
        XCTAssert(keyPath == "name")
    } catch {
        XCTFail()
    }
}

Himotoki supports the following operators to decode JSON elements, where T is a generic type conforming to Decodable protocol.

You can transform an extracted value to an instance of non-Decodable types by passing the value to a Transformer instance as follows:

// Creates a `Transformer` instance.
let URLTransformer = Transformer<String, NSURL> { URLString throws -> NSURL in
    if let URL = NSURL(string: URLString) {
        return URL
    }
    
    throw customError("Invalid URL string: \(URLString)")
}

let URL = try URLTransformer.apply(e <| "foo_url")
let otherURLs = try URLTransformer.apply(e <|| "bar_urls")

• Swift 2.2 / Xcode 7.3
• OS X 10.9 or later
• iOS 8.0 or later (by Carthage or CocoaPods) / iOS 7 (by copying the source files directly)
• tvOS 9.0 or later
• watchOS 2.0 or later

There are 3 options. If your app support iOS 7, you can only use the last way.

Himotoki is Carthage compatible.

• Add github "ikesyo/Himotoki" ~> 2.0 to your Cartfile.
• Run carthage update.

Himotoki also can be used by CocoaPods.

• Add the followings to your Podfile:

  use_frameworks!
  pod "Himotoki", "~> 2.0"

• Run pod install.

• Add this repository as a git submodule:

  $ git submodule add https://github.com/ikesyo/Himotoki.git PATH_TO_SUBMODULE
  
  // or
  
  $ carthage update --use-submodules

• Then just add references of Sources/*.swift to your Xcode project.

Himotoki is released under the MIT License.