How do I translate placeholder text in Rails 4?

Question

I want Rails to automatically translate placeholder text like it does with form labels. How can I do this?

Form labels are translated automatically like this:

= f.text_field :first_name

This helper uses the locale file:

en:
  active_model:
    models:
      user:
        attributes:
          first_name: Your name

Which outputs this HTML

<label for="first_name">Your name</label>

How can I make it so the placeholder is translated? Do I have to type the full scope like this:

= f.text_field :first_name,
    placeholder: t('.first_name', scope: 'active_model.models.user.attributes.first_name')

Is there are easier way?

Answer 1

If using Rails 4.2, you can set the placeholder attribute to true:

= f.text_field :first_name, placeholder: true

and specify the placeholder text in the locale file like this:

en:
  helpers:
    placeholder:
      user:
        first_name: "Your name"

Answer 2

With Rails >= 4.2, you can set the placeholder attribute to true

= f.text_field :first_name, placeholder: true

and in your local file (eg en.yml):

ru:
  activerecord:
    attributes:
      user:
        first_name: Your name

otherwise (Rails >= 3.0) I think you can write something like this:

= f.text_field :attr,
    placeholder: "#{I18n.t 'activerecord.attributes.user.first_name'}"

Answer 3

You can view the source on render at http://rubydoc.info/docs/rails/ActionView/Helpers/Tags/Label to see how Rails does it. It probably doesn't get a lot better than you have, but you could probably swipe some of Rail's logic and stick it in a helper, if you have a lot of them to do. Alternatively, you may consider using a custom form builder to remove some of the repetition in your whole form, not just placeholders.