Allow set message to return a function

[KeironLowe]

It would be good to allow the message attribute on setMessage to allow a function so we have more freedom with our error messages. I'm trying to make the error messages match up with with the errors returned by the server. For example, Laravel returns the following error for a missing field The :attribute field is required. with :attribute being replaced with the name of the field.

So something like...

hyperform.setMessage(element, 'valueMissing', (el) => `The ${el.name} field is required.`);

[Boldewyn]

Yes, agreed. I’ve also already played with such an idea in the context of externally provided translations. The most important part is to get the signature of the callback function right. I.e., what information might be needed in which priority? The current element is very high up on that list, but also the type of validity error, i.e. valueMissing, since one might provide a catch-all function for several error types.

Some other helpful things might involve the default message, that would’ve been given, or the hyperform wrapper object.

I’m a bit torn between the following signatures:

callback(element, error_type, default_message, wrapper)
// or an object:
callback(parameters={element, error_type, default_message, wrapper})
// or a mixture of both:
callback(element, error_type, parameters={default_message, wrapper})

The first is simple and plain, but hard to correct, if we missed anything or the order should change. The second is extremely flexible, but a wee bit cumbersome to handle in the function body. The third is good, if element and error_type are really what one needs in 99.9% of cases from now to eternity. Otherwise it is annoyingly inconsistent to use.

[KeironLowe]

I think I would tend to lead more towards option three as well. Like you mention, that would cover the far majority of use cases and it's easier to extend in the future.