What is the best way to retrieve a Rails variable that is restricted to a specific partial?

Question

What is the best way to retrieve a Rails variable that is restricted to a specific partial?

As a newcomer to Ruby on Rails, I find myself struggling to grasp the larger concept. Any assistance you can offer would be greatly appreciated.

Within my application.html.haml file, I utilize =yield to pull content from ranked.html.haml. Currently, this content has access to the @featured_image rails variable.

My goal is to access the @featured_image rails variable upon page load so that I can preload that image and subsequent images with specific IDs.

Unfortunately, my window.onload = function() in application.html.haml does not have access to @featured_image...any suggestions on how to accomplish this?

Thank you in advance!

javascript ruby-on-rails ruby ajax

Answer 1

Answer №1

As mentioned by Chris Heald, the @featured_image variable is accessible in your views as an instance variable on the controller. To utilize it in javascript, you will need to include it in your layout or partial within a script block similar to this example (using erb syntax):

<script>
  var featured_image="<%= @featured_image %>";
</script>

It's important to handle any possibility of @featured_image being nil and address it accordingly within your application. Chris suggested utilizing a helper function, which is a good approach, but may not be clear for beginners on how to implement it.

Answer 2

As mentioned by Chris Heald, the @featured_image variable is accessible in your views as an instance variable on the controller. To utilize it in javascript, you will need to include it in your layout or partial within a script block similar to this example (using erb syntax):

<script>
  var featured_image="<%= @featured_image %>";
</script>

It's important to handle any possibility of @featured_image being nil and address it accordingly within your application. Chris suggested utilizing a helper function, which is a good approach, but may not be clear for beginners on how to implement it.

Answer 3

Answer №2

When @featured_image is assigned from a controller, it becomes visible to all views in the render pipeline. However, one should not always assume its visibility as a layout can render multiple pages. It is advisable to validate its presence before using it in the layout.

I suggest employing a helper method to ensure it is not nil and then outputting the appropriate markup. Another option to consider is using content_for, which allows you to specify sections of markup to be rendered in different parts of the layout.

Answer 4

When @featured_image is assigned from a controller, it becomes visible to all views in the render pipeline. However, one should not always assume its visibility as a layout can render multiple pages. It is advisable to validate its presence before using it in the layout.

I suggest employing a helper method to ensure it is not nil and then outputting the appropriate markup. Another option to consider is using content_for, which allows you to specify sections of markup to be rendered in different parts of the layout.

What is the best way to retrieve a Rails variable that is restricted to a specific partial?

Answer №1

Answer №2

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