First, a disclaimer, I didn’t think too much about this idea so maybe there is already a better solution or even if this is possible giving GraphQL constraints.

The idea is to “replicate” the validate functionality of LV’s form validation but in the API’s generated by AshGraphql.

For example, right now, AFAIK, the only way to validate a create/update form using AshGraphql’s generated apis is to either submit the full form and get the errors, or to duplicate the validation in the frontend.

I was wondering if we could do something like adding a special field called validate_only or something like that that would allow the following:

1. Send the form with only a subset of the fields so the frontend can just send fields that the user filled and get validation for them only.

2. Only apply the changeset constraints and return instead of creating/updating the resource (basically replicating the functionality of a form validate).

Obs. Maybe (1) would not be possible with just the validate_only flag since the frontend graphql validation would block the user from sending fields that can’t be nullable? In that case, maybe another approach would be to add an option to the action in the graphql block that would generate another action only for validation where all fields can be nullable (or some other special type that indicates it is not filled yet), example:

graphql do
  mutations do
    create :create, :create, include_validation?: true
  end
end

This would create a validateCreateResource api in graphql side besides the createResource api.