How to validate fields using Swift? I wanted to do with Exception, but I just searched and found that Swift has no Exceptions ...
I would like something like this:
void onCadastrar(dados){
try {
validarNome(dados.nome)
validarSenha(dados.senha)
...
etc
} catch(MinhaException erro){
//Alert da mensagem de erro
}
}
Is this possible in SWift?
Actually Swift does not have a try catch, but rather has exceptions, as Apple documentation .
As @bigown mentioned, even in languages that have try catch this should only be used in some situations.
Now to accomplish what you want I also indicate the good old if .
Something like:
if dadosValidos() {
enviarDados()
} else {
exibeMensagemErro()
}
Now if you are making a framework to be used by third parties, to capture it will have to check with if and then throw a fatalError() with the message, but this forces the application to stop.
You can try to use a type called guard
guard let nome = dados.nome { print(erro) return }
resto do codigo
or if not, using itself
if let nome = dados.nome{ codigo}
In case, if it is possible to assign it means that the field is not null
Was that what you needed?
Although other alternatives are recommended, it is possible to do this yes, I already asked myself the same question using this same field validation case and I solved it as follows:
You can first make an enum to list all possible error types that will be returned
enum ValidatingError: Error {
case invalidName
case invalidPassword
}
Make an extension to specify the return of each error
extension ValidatingError: LocalizedError {
public var errorDescription: String? {
switch self {
case .invalidName:
return NSLocalizedString("ERRO no nome", comment: "Coloque um nome com mais de 3 letras")
case .invalidPassword:
return NSLocalizedString("Erro na senha", comment: "A senha deve conter 6 ou mais caracteres")
}
}
}
Create the validation functions
func valida(_ nome: String) throws {
if nome.count <= 3{
throw ValidatingError.invalidName
}
}
func valida(_ senha: String) throws {
if senha.count <= 6{
throw ValidatingError.invalidPassword
}
}
And to call the way you specified is to just call the methods inside and one of the catch
func onCadastrar(dados: Dados){
do {
try valida(dados.nome)
try valida(dados.senha)
} catch {
print(error)
}
}