In Swift, when JSON purge, it is passed in the snake case and troublesome coping method

1.First of all

――As the title says, it is described as a memorandum. ――For camel case and snake case, please check with Google teacher. --Example: https://designsupply-web.com/media/developmentlab/4052/

2. version

• Xcode12
• Swift 5.0 --No GitHub (you can use it as it is by copying and pasting)

3. 3. When received in camel case

When the API format is camel case when received by API. Simply put, if you can use it as it is.

import Foundation

struct Response: Codable {
    ///name
    let firstName: String
    ///Last name
    let lastName: String
}

///received data
var json = """
{
"firstName": "Yamada",
"lastName": "Taro"
}
"""

let data = json.data(using: .utf8)!

///Decoding process
let model = try! JSONDecoder().decode(Response.self, from: data)

print(model)

4. There is a way to receive in the snake case in the parameter of JSONDecoder

let jsonDecoder = JSONDecoder()
jsonDecoder.keyDecodingStrategy = .convertFromSnakeCase

Encode above. However, this alone cannot be used automatically, so cut ʻenum, which is a derivative of CodingKey`, in the receiving structure. It looks like the following

struct Response: Codable {
    ///name[first_name]
    let firstName: String
    ///Last name[last_name]
    let lastName: String

    private enum CodingKeys: String, CodingKey {
        case firstName
        case lastName
    }
}

5. Summary

With the following implementation, even if the API automatically returns in the snake case, it can be used in the camel case structure on the code side. Ah convenient (If you know it, it's not a big story, though)

import Foundation

struct Response: Codable {
    ///name[first_name]
    let firstName: String
    ///Last name[last_name]
    let lastName: String

    private enum CodingKeys: String, CodingKey {
        case firstName
        case lastName
    }
}

///received data
var json = """
{
"first_name": "Yamada",
"last_name": "Taro"
}
"""

let data = json.data(using: .utf8)!

///Decoding process
let jsonDecoder = JSONDecoder()
jsonDecoder.keyDecodingStrategy = .convertFromSnakeCase
let model = try! jsonDecoder.decode(Response.self, from: data)

print(model)

The end