Swift - JSONEncoder on generics

Question

How can I send generic struct to a function that returns a JSON?

Im trying to make a func that gets a struct as a parameter and returns a JSON data. Im making it because I want to avoid repetition and it will be used in several places and with different structs (ie: user, client, contact...)

struct User : Codable {
    let email: String
    let password: String
}

func makeJSONData<T>(_ value: T) -> Data {
    var jsonData = Data()
    let jsonEncoder = JSONEncoder()

    do {
        jsonData = try jsonEncoder.encode(value)
    }
    catch {
    }
    return jsonData
}

By using makeJSONData, I get an error: Argument type 'T' does not conform to expected type 'Encodable'

let user = User(email: emailTextField.text!, password : passwordTextField.text!)
let user2 = makeJSONData(user)

change method declaration to func makeJSONData<T: Codable>(_ value: T) -> Data — Mukesh
– Mukesh, Commented Jan 29, 2018 at 5:10

Quoc Nguyen · Accepted Answer · 2018-09-18 23:37:47Z

2

because of you don't define the type of T, just change

makeJSONData<T>

to

makeJSONData<T: Codable>

edited Sep 18, 2018 at 23:37

answered Jan 29, 2018 at 5:16

Quoc Nguyen

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2 Comments

Renan Aguiar Over a year ago

By following Mukesh`s answer, it worked. Quoc Nguyen, there is a typo on your commend.

Quoc Nguyen Over a year ago

@RenanAguiar yeah, fixed it. Thanks

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