How to include ActionView helpers in the assets pipeline?

Question

How to include Rails view helpers to be accesible by assets pipeline execution context?

An example use case would be to generate the markup for a form, using form_tag helper method, and make it available to a Javascript template (like handlebars, jst, etc.).

I use handlebar_assets gem, but this should apply to any erb or haml template too.

Ozellaozen

Answer 1

Create a inititializer and include the helpers in the context of the assets like this:

Rails.application.assets.context_class.class_eval do
  include ActionView::Helpers
  include MyAppHelper
  include Rails.application.routes.url_helpers
end

Taken from this sprockets issue

Ozellaozen

This also worked for me when I wanted to render a custom ERB to string with template = ERB.new(html) template.result(binding). Without this I wasn't able to use concat and other simple helpers. – Birdwell

@brutuscat, can you clarify where you would put this code? Thanks – Lanielanier

@Lanielanier no problem: "Create a inititializer", see more here guides.rubyonrails.org/configuring.html#using-initializer-files – Ozellaozen

reference: github.com/rails/sprockets-rails/issues/… – Firebrick

Answer 2

The above answer is now out of date. As of sprockets-rails 3, the appropriate interface is a configure block, like so:

Rails.application.config.assets.configure do |env|
  env.context_class.class_eval do
    # include SomeHelper
  end
end

This configure block should still be placed in an initializer.

reference: https://github.com/rails/sprockets-rails/issues/307#issuecomment-170707886

Firebrick