error-handling.md

Error handling on ViewModel and Submission

During ViewModel retrieval and Submission processing things can go wrong. In order to capture these errors you can throw a FormException.

This exception will be caught and converted into a FormError object which will be returned to the frontend.

FormException also has a component property in case you want the message to be displayed for a specific component.

Leaving the component empty will result in a message above the form.

During the execution of commands you are also able to throw a FormException.

FormException:

class FormException(
    message: String,
    val component: String? = null,
    cause: Throwable? = null
) : Exception(message, cause)

This is the JSON representation of the error:

{
  "error": "...",
  "component": "componentName"
}

Form field error rendered above the form field

Form error rendered above the form

During command handling you can also throw a BusinessException. This is similar to FormException but it will only show on top of the form

BusinessException:

class BusinessException(
    message: String,
    cause: Throwable? = null
) : Exception(message, cause)