validate
protected open fun validateSignIn(email: String, password: String, language: String, custom: Array<Any>): String
Method to validate the inputs of the signIn method to correctly execute a sign-in operation
Return
the key of the error if any inputs is wrong, null otherwise as String
Parameters
email
: the email of the user
password
: the password of the user
language
: the language of the user
custom
: the custom parameters added in a customization of the EquinoxUser to execute a customized sign-in validation