HAML / Ruby Loop variable being appended with Content_For

Question

I have a YAML file of products:

# Product - Granola Bar
-   title       : "Granola Bar"
    excerpt     : "Comes in several amazing varieties including nut, and delicious fruit."
    description : "Comes in several amazing varieties including nut, and delicious fruit."
    image       : "granola-bar.jpg"
    cost        : "3.50"
    discount    : "2.50"
    stock       : "100"
    ingredients :
        - value : key

# Product - Granola Bar
-   title       : "Hazelnut Spread"
    excerpt     : "Chocolate"
    description : "Chocolate"
    image       : "hazelnut-spread.jpg"
    cost        : "2.50"
    discount    : "1.50"
    stock       : "100"
    ingredients :
        - value : key

When I iterate through these the content is being appended to the previous one's content variable:

"Comes in several amazing varieties including nut, and delicious fruit. 3.50"
"Comes in several amazing varieties including nut, and delicious fruit. 3.50 Chocolate 2.50"

But it should be:

"Comes in several amazing varieties including nut, and delicious fruit. 3.50"

then

"Chocolate 2.50"

I'm using:

-# Create new array for the thumbnails
- thumbnails  = []

-# Loop through the array
- data.products.each do | product |

    -# Content
    - content_for :content do

        -# Excerpt
        = product.excerpt

        -# Cost
        = product.cost

    - content = yield_content :content

    - thumbnails << { :"data-src" => "holder.js/300x200/auto",
                      :caption    => content,
                      :title      => product.title }

I'm not sure what to search for, mutable variables in a loop? I tried putting content = nil before the loop and inside also to unset it at each pass.

I want to save the content_for to push into a partial.

This is an image of what is happening. It should obviously not be doubled up in the second thumbnail:

enter image description here

I'm not sure from your description what the difference between the expected and actual output is. — Jim Jeffries, Feb 17 '14 at 15:31
Hiya - its whats between the two sets of quotes. the "should be" does not have the first iteration prepended to it. This is built from the excerpt and cost from the yaml file — Ian Warner, Feb 17 '14 at 15:38
Hiya - image says it a thousand times better - as you can see from the second thumb the content is being duplicated somewhere in the loops. I want to reset these variables on each iteration basically - is possible. — Ian Warner, Feb 17 '14 at 15:48

score 2 · Accepted Answer · edited Feb 07 '20 at 17:12

content_for is used to capture content that is used in a different place.

If you have yield_content :title in your application layout and you set it in the currently rendered partial:

# index.haml
- content_for :title, "I'm on the index page"

Your example should NOT use content_for at all. It should just render the strings into the output:

- data.products.each do |product|
  = product.excerpt
  = product.cost

If you want to use that output in a img_tag helper or something like that, than use a helper method to generate the content or put it into its own partial if the logic is more complex.

You can also assign new variables in the view code and use them later on:

- caption = "#{product.excerpt} #{product.cost}"

I don't see a need for anything like that in your example at all. Maybe that's because you actually never use "thumbnails" anywhere.

You are correct - I have edited the question to show that I need to push this content into a partial also. — Ian Warner, Feb 18 '14 at 10:30

score -2 · Answer 2 · answered Feb 19 '14 at 13:46

-2

In the end I changed to using capture_html

    -# Loop through the array
- data.products.each do | product |

    -# Content
    - capture = capture_html do

        -# Excerpt
        %p
            = product.excerpt

        -# Page Name
        - page = product.title.downcase.gsub( /[^a-z0-9\- ]/, ' ').gsub( / /, '-' )

        -# Button
        = partial "bootstrap/css/button",
                   :locals => { :color      => "primary",
                                :content    => "View Product",
                                :extraClass => "pull-right",
                                :href       => "/shop/#{ page }" }

        -# Cost
        %p.text-left.price
            &pound;
            = product.cost

        .clearfix

    - thumbnails << { :"data-src" => "holder.js/300x200/auto",
                      :caption    => capture,
                      :title      => product.title  }

answered Feb 19 '14 at 13:46

Ian Warner

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that is not a good way of doing it. put the capture block in it's own partial, use `render` to get the output. at best, use a helper to wrap the render call. – phoet Feb 21 '14 at 13:31
did it deserve the down votes though? So a little refactoring is required but the code itself is ok? – Ian Warner Feb 22 '14 at 14:10
yeah, i think the answer is harmful for others – phoet Feb 22 '14 at 15:00
yeah, i think it's not useful for others. – phoet Feb 23 '14 at 17:21

HAML / Ruby Loop variable being appended with Content_For

2 Answers2