Rails Formtastic: adding “data-” field to option tag with value from related table

Question

Thanks to Rails Formtastic: adding "data-" field to option tag I got an easy solution to adding a data fieed to options in my ActiveAdmin form. But, now I want to get the data value from a different table (model). I'm a total rails newbie, trying to figure things out as I go, hoping someone can steer me right on this.

So, I have this in my ActiveAdmin form:

att.input :attribute, :label => "Attribute:", :as => :select, :collection => AttributeDefinition.all.map { |adef| [adef.attribute_name, adef.id, {:"data-type" => AttributeInputType.where(:id => adef.input_type_id).select("input_type") } ] }

What I'm hoping to end up with is a select element with options like this:

<option data-type="dropdown" value="4">Voltage</option>

But instead, I am getting options like this:

<option data-type="#<ActiveRecord::Relation:0x6adb3f8>" value="4">Voltage</option>

This is for a Product model, which has_many :attribute_definitions, through: :product_attributes, and each AttributeDefinition belongs_to :input_type, class_name: "AttributeInputType". So I am trying to reach the input_Type field (string) of the AtributeInputType which matches the input_type_id of the AttributeDefinition (adef.input_type_id above).

I can get the ID, and the data-type attribute is generated ok, so I think my problem is just basic not knowing how to pull that string field by ID. Anyone can point me in the right direction? Thanks!

Answer 1

replace this

AttributeInputType.where(:id => adef.input_type_id).select("input_type")

with

adef.input_type.input_type

adef.input_type returns the AttributeInputType object associated with adef. .input_type returns the input_type attribute of the AttributeInputType object.

In case adef does not have any input_type the above statement would throw an error. So a more robust option is

 adef.input_type.try(:input_type)

try returns nil if the associated object is not found.