Cannot(?) validate that either field A or field B be filled.

[Mamsaac]

Validation logic for requiring one of either fields to be filled, but not requiring both necessarily has to be done outside of the form definition.

While not a big deal, since it feels like the purpose of validators is to save the programmer to add extra validation logic outside from form creation, it would be nice to have the possibility to define a validator that gets executed when field.data is empty and the field is not required.

[ljharb]

Can you give me an example of a use case for this? Typically whenever I've seen this, it's because the schema is in desperate need of a refactor.

[Mamsaac]

User has to define emergency contacts for a given situation. We accept require the user giving either the e-mail or the cellphone number of the contact. If both are provided, the contact is done via both ways; if only the e-mail or the cellphone is given, then only via either way they will be contacted. If non is given, the emergency contact is not accepted, since there's no way to contact him/her.

[ljharb]

Interesting! I'll have to think about what sort of API would make sense for that, and how much complexity that would add to forms. If it can be added simply, then awesome, otherwise I'll end up suggesting that you just check that yourself :-)

[Mamsaac]

At the moment I do check it out myself.

I'm full of work at the moment, else I would love to contribute to this. If I find myself with a free day, be sure I will try to contribute to this :)

I'm looking forward to the nested forms being on stable branch! thanks for all the good work.