Requirements

About

The project objective is to enhance the usage experience of the Codable protocol using the macro provided by Swift 5.9 and to address the shortcomings of various official versions.

Feature

• Default value
• Basic type automatic convertible, between String Bool Number etc.
• Custom multiple CodingKey
• Nested Dictionary CodingKey
• Automatic compatibility between camel case and snake case
• Convenience Codable subclass
• Transformer

Installation

CocoaPods

pod 'CodableWrapper', :git => 'https://github.com/winddpan/CodableWrapper.git'

Swift Package Manager

https://github.com/winddpan/CodableWrapper

Example

@Codable
struct BasicModel {
    var defaultVal: String = "hello world"
    var defaultVal2: String = Bool.random() ? "hello world" : ""
    let strict: String
    let noStrict: String?
    let autoConvert: Int?

    @CodingKey("hello")
    var hi: String = "there"

    @CodingNestedKey("nested.hi")
    @CodingTransformer(StringPrefixTransform("HELLO -> "))
    var codingKeySupport: String

    @CodingNestedKey("nested.b")
    var nestedB: String

    var testGetter: String {
        nestedB
    }
}

final class CodableWrapperTests: XCTestCase {
    func testBasicUsage() throws {
        let jsonStr = """
        {
            "strict": "value of strict",
            "autoConvert": "998",
            "nested": {
                "hi": "nested there",
                "b": "b value"
            }
        }
        """

        let model = try JSONDecoder().decode(BasicModel.self, from: jsonStr.data(using: .utf8)!)
        XCTAssertEqual(model.defaultVal, "hello world")
        XCTAssertEqual(model.strict, "value of strict")
        XCTAssertEqual(model.noStrict, nil)
        XCTAssertEqual(model.autoConvert, 998)
        XCTAssertEqual(model.hi, "there")
        XCTAssertEqual(model.codingKeySupport, "HELLO -> nested there")
        XCTAssertEqual(model.nestedB, "b value")

        let encoded = try JSONEncoder().encode(model)
        let dict = try JSONSerialization.jsonObject(with: encoded) as! [String: Any]
        XCTAssertEqual(model.defaultVal, dict["defaultVal"] as! String)
        XCTAssertEqual(model.strict, dict["strict"] as! String)
        XCTAssertNil(dict["noStrict"])
        XCTAssertEqual(model.autoConvert, dict["autoConvert"] as? Int)
        XCTAssertEqual(model.hi, dict["hello"] as! String)
        XCTAssertEqual("nested there", (dict["nested"] as! [String: Any])["hi"] as! String)
        XCTAssertEqual(model.nestedB, (dict["nested"] as! [String: Any])["b"] as! String)
    }
}

Macro usage

@Codable

• Auto conformance Codable protocol if not explicitly declared

  // both below works well
  
  @Codable
  struct BasicModel {}
  
  @Codable
  struct BasicModel: Codable {}

• Default value

  @Codable
  struct TestModel {
    let name: String
    var balance: Double = 0
  }
  
  // { "name": "jhon" }

• Basic type automatic convertible, between String Bool Number etc.

  @Codable
  struct TestModel {
    let autoConvert: Int?
  }
  
  // { "autoConvert": "998" }

• Automatic compatibility between camel case and snake case

  @Codable
  struct TestModel {
    var userName: String = ""
  }
  
  // { "user_name": "jhon" }

• Member Wise Init

  @Codable
  public struct TestModel {
    public var userName: String = ""
  
    // Automatic generated
    public init(userName: String = "") {
        self.userName = userName
    }
  }

@CodingKey

• Custom CodingKeys

  @Codable
  struct TestModel {
    @CodingKey("u1", "u2", "u9")
    var userName: String = ""
  }
  
  // { "u9": "jhon" }

@CodingNestedKey

• Custom CodingKeys in nested dictionary

  @Codable
  struct TestModel {
    @CodingNestedKey("data.u1", "data.u2", "data.u9")
    var userName: String = ""
  }
  
  // { "data": {"u9": "jhon"} }

@CodableSubclass

• Automatic generate Codable class's subclass init(from:) and encode(to:) super calls

  @Codable
  class BaseModel {
    let userName: String
  }
  
  @CodableSubclass
  class SubModel: BaseModel {
    let age: Int
  }
  
  // {"user_name": "jhon", "age": 22}

@CodingTransformer

• Transformer between in Codable / NonCodable model

  struct DateWrapper {
    let timestamp: TimeInterval
  
    var date: Date {
        Date(timeIntervalSince1970: timestamp)
    }
  
    init(timestamp: TimeInterval) {
        self.timestamp = timestamp
    }
  
    static var transformer = TransformOf<DateWrapper, TimeInterval>(fromJSON: { DateWrapper(timestamp: $0 ?? 0) }, toJSON: { $0.timestamp })
  }
  
  @Codable
  struct DateModel {
    @CodingTransformer(DateWrapper.transformer)
    var time: DateWrapper? = DateWrapper(timestamp: 0)
  
    @CodingTransformer(DateWrapper.transformer)
    var time1: DateWrapper = DateWrapper(timestamp: 0)
  
    @CodingTransformer(DateWrapper.transformer)
    var time2: DateWrapper?
  }
  
  class TransformTest: XCTestCase {
    func testDateModel() throws {
        let json = """
        {"time": 12345}
        """
  
        let model = try JSONDecoder().decode(DateModel.self, from: json.data(using: .utf8)!)
        XCTAssertEqual(model.time?.timestamp, 12345)
        XCTAssertEqual(model.time?.date.description, "1970-01-01 03:25:45 +0000")
  
        let encode = try JSONEncoder().encode(model)
        let jsonObject = try JSONSerialization.jsonObject(with: encode, options: []) as! [String: Any]
        XCTAssertEqual(jsonObject["time"] as! TimeInterval, 12345)
    }
  }

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