vuelidate: Is there a way to programmatically force an error?

I would just like to add/endorse that formal support for this action of accepting error messages from the server would be super awesome. When doing an AJAX form submit, there’s always the chance of a server-side validation test failure, even if they are all intended to be checked first client-side a programming error might mean a server-side check catches it. In particular, doing form submissions to a public JSON API interface which good-practice design requires it performs its own validation checks before committing changes. The main reasons why this concerns this validation framework are:

• The from-the-server error condition should be considered as cleared when the field is next edited, so such errors should be cleared when “$dirty()” occurs and without attempting to perform another validation test on these error messages. Of course this can be done externally to the validation package but I am just figuring this would be a common use case, or at least would be if offered.
• The API error response may provide multiple error conditions for a given form field and it may be desired to display them all. This makes it unique from other test cases in this package, which will always only evaluate one test condition and will only ever have one message associated with each of them.

The method above herein is a good patch solution but probably not quite robust enough. I don’t just mean to be Mr. Negative Nelly… I am going to poke at solutions for this, and if I hit on something which might work well in a PR I will share, but beforehand just want to share my thoughts in case there are different opinions about this.

@Frizi

Yes! That’s the bit I was missing! 😄

And reading back to your original suggestion, you did mention it… my mistake.

Working fiddle for anyone coming across this thread

https://jsfiddle.net/doginthehat/LoLbfsoe/

Help much appreciated

I iterated on @doginthehat example and added server errors for two fields separately.

https://jsfiddle.net/duleorlovic/0tdpu32a

Based on error response from server we show error on specific fields. Server errors are checked in .catch response for validationPromise and we clear validationPromise on update for those fields which can produce server errors.

I finally ended with a errors object in my data populated by my promise error callback. As my API return an error json object containing fields errors, it allows me to have custom validator which will check in this errors object if the field exist to return a true or false. And then, it’s easy to display the message associated in the v-if that display error messages.

You should add validationPromise to data field, so it can be observable. Then the validator will kick in when you assign it and rerun when the promise state changes.