ResOkIf(Boolean, String) Method
            Returns back the Err if this is Err.
            Otherwise, returns Ok if 
okCondition holds; Err if it does not hold.
            Especially useful in fluent input validation.
            
static Res<User> Login(string username, string passwordHash)
{
    return OkIf(!string.IsNullOrEmpty(username))    // validate username
        .OkIf(!string.IsNullOrEmpty(passwordHash))  // validate password-hash
        .OkIf(userRepo.ContainsKey(username))       // further validate user
        .Map(() => GetUser(username, password));    // finally map into actual result;
                                                    // any Err in validation steps will directly be mapped to Err, avoiding GetUser call.
}
Namespace: Orx.Fun.ResultAssembly: Orx.Fun.Result (in Orx.Fun.Result.dll) Version: 1.3.0+344c8bdd6f720ccfb2d8db7c61b76cf02be18f5f
public Res OkIf(
	bool okCondition,
	string strOkCondition = ""
)
- okCondition  Boolean
 - Condition that should hold to get an Ok, rather than Err.
 - strOkCondition  String  (Optional)
 - Name of the condition; to be appended to the error message if it does not hold. Omitting the argument will automatically be filled with the condition's expression in the caller side.
 
Res