<@U02SEA99VJB> Akkurate works really well in our p...

# akkurate

[audax]

@Johann Pardanaud Akkurate works really well in our project. Thank you for solving our problem! ❤️

[Johann Pardanaud]

This is SO appreciated, thank you for taking the time to write this message 🙏

[Johann Pardanaud]

Do you feel there any missing features? Some misunderstandings?

[Johann Pardanaud]

And remember me, what were you using before? Konform?

[audax]

We were using Konform at first, yes.

[audax]

We are using hierarchical contexts, so that we are able to build the validation logic step by step. E.g. we are passing a reference date which is used in many validations.

[audax]

The main feature we'd like is probably i18n support, which in our case means that instead of an error message, we'd like to build a tuple of message-key and values that are later interpolated in the applications.

[audax]

But since our old system didn't do that properly anyway, it's absolutely not a blocker 😄

[audax]

At the moment we have many, many different validation messages and attach them via "otherwise".

[Johann Pardanaud]

If I understand properly, you would like to be able to do something like this?

isNotEmpty() otherwise {
    "not-empty-message".populateWith(value1, value2, value3)
}

Where not empty-message is an identifier declared somewhere else with its message and contains slots for the values:

translations.en_US["not-empty-message"] = "Should not be empty: %s, %s, %s"

translations.fr_FR["not-empty-message"] = "Ne devrait pas être vide: %s, %s, %s"

(this is a draft, everything here is subject to change 😄)

[Johann Pardanaud]

Do you already use a library to handle localization of your strings? Ideally, I would prefer to plug to existing tools.

[audax]

We already use a proprietary library to handle translations in the frontend, where we translate in demand. We don't need translated and populated strings, but just the raw values to translate and interpolate in the frontend.

[audax]

This is one of the more complex validations which shows some special cases (it's a stupid TO-Interface, but that's a problem for later! 😉 😞

class EmployeeBirthDateValidationContext(
    val currentDate: LocalDate
)

val birthDateValidation = Validator<EmployeeBirthDateValidationContext, EmployeeBirthData?> { context ->

    if (birthDate.unwrap() == null) {

        fictiveBirthDate.isNotNull() otherwise { BirthDateErrorKey.MUST_NOT_BE_EMPTY.key }
        fictiveBirthDate.birthYear.isNotNull() otherwise { BirthDateErrorKey.FICTIVE_BIRTH_YEAR_MUST_NOT_BE_EMPTY.key }
        fictiveBirthDate.birthYear.isGreaterThanOrEqualTo(1900) otherwise { BirthDateErrorKey.FICTIVE_BIRTH_YEAR_MIN_1900.key }
        fictiveBirthDate.birthYear.isLowerThanOrEqualTo(2999) otherwise { BirthDateErrorKey.FICTIVE_BIRTH_YEAR_MAX_2999.key }
        
        if (fictiveBirthDate.birthMonth.unwrap() != null) {
            fictiveBirthDate.birthMonth.isBetween(1..12) otherwise { BirthDateErrorKey.FICTIVE_BIRTH_MONTH_MUST_NOT_BE_BETWEEN_1_AND_12.key }
        }
    } else {

        birthDate.isNotNull() otherwise { BirthDateErrorKey.MUST_NOT_BE_EMPTY.key }
        birthDate.map { it?.toKotlinLocalDate()?.year }
            .isGreaterThanOrEqualTo(1880) otherwise { BirthDateErrorKey.YEAR_MUST_BE_1880_OR_LATER.key }

        birthDate.asDate().isBeforeOrEqualTo(
            context.currentDate.minus(
                12,
                DateTimeUnit.YEAR
            )
        ) otherwise { BirthDateErrorKey.MUST_BE_AT_LEAST_12.key }
    }
}

[Anastasios Georgousakis]

Also, for us i18n support and the ability to send error information with i18n keys and required parameters and context is the feature that is missing from you library. We are using valiktor and we cannot migrate to akkurate because of that. With valiktor we can have localized messages with parameters and also we can send all the details of a validation error (error code, value that failed, parameters for the error message, etc) back to UI so that we can localise the errors their.

[Johann Pardanaud]

@audax Thank you for the code sample, this will help a lot! Do you have a sample of the data your frontend currently receives? I imagine it contains the message keys but also some raw values?

[Johann Pardanaud]

@Anastasios Georgousakis That's really interesting! Do you handle localization on the backend? Would you be open to provide me a code sample?

[audax]

Our frontend receives just the datapath and the message key for each issue.

[audax]

@JsExport
fun validateEmployee(employee: Employee, payslipMonth: SharedDate): Array<ValidationError> =
    when (val result = employeeValidation(
        EmployeeValidationContext(
            payslipMonth.toKotlinLocalDate()
        ),
        employee)) {
        is ValidationResult.Failure -> result.violations.byPath.map { (path, violations) ->
            ValidationError(
                path.joinToString("."),
                violations.first().message
            )
        }.toTypedArray()
        else -> arrayOf()
    }

[audax]

and in the react application:

function validationErrorsToHookFormFieldErrors(validationErrors: ValidationError[]) {
    return mapValidationErrorsToFields(validationErrors).reduce(
      (allErrors, currentError) => ({
        ...allErrors,
        [`${currentError.dataPath}`]: {
          type: "validation",
          // @ts-ignore
          message: t(currentError.message),
        },
      }),
      {}
    );
  }

[audax]

[still very much WIP 😉 ]

[Johann Pardanaud]

So, help me understand. What are you missing in all this code? The raw values?

Your use case would be to write the raw value inside the localized message?

[audax]

What I would love to be able to do:
message: t(currentError.message, currentError.additionalData)
and I specify the additional data via otherwise { (BirthDateErrorKey.MUST_BE_AT_LEAST_12.key, birthDate, fictiveBirthDate.year) }

[Johann Pardanaud]

Great! That was exactly what I needed to understand 🙂

[Johann Pardanaud]

I will add this to the feature list 😄

[Johann Pardanaud]

Thank you so much for yout time 🙏

[audax]

🥰

[Anastasios Georgousakis]

@Johann Pardanaud have you checked how i18n is supported in valiktor? Their implementation is tight coupled with Java resource bundles but it can help you provide localised messages either on backend either as response with all data UI needs to construct a validation error. Also, you can override or add translations for other languages for all the predefined validations without having to use otherwise. I think valiktor is the only kotlin validation library that supports that but nobody maintains it anymore. Something like that it is multiplatform will be great if you can provide.

[Johann Pardanaud]

I would love to provide this! You're right, I will take inspiration from Valiktor, since its already there and it does the job well. Thank you for your help 🙂

[audax]

I would just like to not send the translated message, but instead a message key with optional arguments, but I guess if the types are generic enough, that should be possible with such a system.

[audax]

So my translated message would be not a string, but instead an object with all the data needed by the frontend to display the message properly.

[Johann Pardanaud]

I think I can work with both requirements: one with raw data to translate on the frontend, one with a translation library integrated in the backend.