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What is it?

enum + imitation = Enumitation


Ever wanted to restrict an ActiveRecord attribute to specific values, but thought a join table to contain the values and a foreign key constraint were overkill? Well, you could opt for an enum field, but maybe your DBMS doesn't support enums. Or maybe it does, but you just aren't in the mood for an enum field today.

Also, do you need to provide these values as options in a select form field?

Enumitation exists to allow restrictions on ActiveRecord attribute values without the need for a join table or enum field, while also providing those values for the purpose of options in a select field in a form.


class Publisher < ActiveRecord::Base
  enumitation :location, %w[US CA]

Here we've specified that we want the location attribute to be an enum with the values US and CA. The enumitation method does two important things:

  • it adds a validates_inclusion_of validation to the model, using the values specified when declaring the enumitation
  • it provides a select_options_for method that can be used to provide a select tag with options

In the console:

publisher = location: 'MX'
publisher.valid?   #=> false
publisher.errors   #=> {:location=>["is not included in the list"]}
publisher.location = 'US'   #=> "US"
publisher.valid?   #=> true

Publisher.select_options_for :location   #=> [["US", "US"], ["CA", "CA"]]

Custom Labels (i18n)

You can provide alternate labels for your values in your locale files. These labels will be returned from the select_options_for method.

In config/locales/en.yml:

          US: 'United States'
          CA: 'Canada'

Now when calling the select_options_for method:

Publisher.select_options_for :location   #=> [["United States", "US"], ["Canada", "CA"]]

So, from your view:

= form_for :publisher do |f|
  = :location, Publisher.select_options_for(:location)

But this is no big deal!

I know. It really isn't that big of a deal, and it wouldn't take that much effort to reproduce by hand what Enumitation provides. But why do all that work when you can get it from a one-liner?

There are other gems that practically do the same thing.

True, but the ones I found either didn't fit my needs or they did so much more than I needed. I wanted something that fit my needs exactly and nothing more.


bundle exec rspec spec


If you think Enumitation could be better, fork away and send a pull request! Please make sure to include specs for your changes.

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