How to write correct view helper

Phoenix Forum Questions / Help
1 
defmodule Promo.OrderView do
  use Promo.Web, :view
 alias Promo.Page

 def page_title(page = %Page{}) do
    for {tag, class} <- [h5: "hide-on-small-only", h6: "hide-on-med-and-up"] do
      content_tag tag, class: class do
        page.title <> page_sub_title(page.sub_title)
      end
    end
  end

   def page_sub_title(nil), do: ""
   def page_sub_title(sub_title) do
     "<br><small>" <> sub_title <> "</small>"
  end
end

In view i see escaped html string with small and etc.
How to write helper function ā€œpage_titleā€ what return to me:
h2 title + br + small sub_title /small /h2, but
only h2 title /h2 if sub_title do not exists??

1 Like
2

For any view helpers, first I have these at the top of my module:

  import Phoenix.HTML
  import Phoenix.HTML.Form
  import Phoenix.HTML.Link
  import Phoenix.HTML.Tag

Just for convenience sakes.

However, to do what you want:

  def page_sub_title(nil), do: ""
  def page_sub_title(sub_title) do
    ~e"""
    <br><small><%= sub_title %></small>
    """
  end

The ~e sigil when you import the Phoenix view stuff gives you inline ā€˜eexā€™ templating, just like eex files. This is the best way to work with it.

However, you can always wrap your output in a {:safe, content} tuple, but that is not recommended unless you are sure it is entirely safe, and considering I do not see where sub_title is coming from (possibly user input through database or so), Iā€™d use eex to make sure everything gets properly escaped or bad bad bad things can happen.

5 Likes
3

Thanks for reply!
But now i have an error ā€œargument errorā€ in view.
This code does not work

defmodule Promo.OrderView do
  use Promo.Web, :view
  alias Promo.Page

  def page_title(page = %Page{}) do
    for {tag, class} <- [h5: "hide-on-small-only", h6: "hide-on-med-and-up"] do
      content_tag tag, class: class do
        page.title <> page_sub_title(page.sub_title)
      end
    end
  end

  def page_sub_title(nil), do: ""
  def page_sub_title(sub_title) do
    ~e{<br><small><%= sub_title %></small>}
  end
end
4

I find correct answer. Thanks for help

def page_title(page = %Page{}) do
    for {tag, class} <- [h5: "hide-on-small-only", h6: "hide-on-med-and-up"] do
      content_tag tag, class: class do
        do_page_title(page.title, page.sub_title)
      end
    end
  end

  defp do_page_title(title, nil), do: title
  defp do_page_title(title, sub_title) do
    ~e{<%= title %><br><small><%= sub_title %></small>}
  end