What's the best way to setup a conditional to see if a matrix block is used?

Question

I need to add some javascript to a page depending upon whether or not a matrix block is used, one is for a slideshow block to load responsiveslides.js, another is for a video block to load fitvid.js. If I place it in the loop then I will get the javascript repeated for each time an entry uses that matrix block. I'm looking to add this towards the bottom of the template and load the .js files once each if the block is used in a loop above. What's the best way to do this?

Answer 1

I would use a loop to set a conditional, and then check it afterwards. You need to initialize the conditional outside of the loop, otherwise it won't be set outside the loop later.

{% set haveAVideo = false %}
{% for block in matrixBlocks %}
  {% if block.type == 'video' %}
    {% set haveAVideo = true %}
  {% endif %}
{% endfor %}

{% if haveAVideo %}
  {# video block js #}
  {% includeJsFile ... %}
{% endif %}

Answer 2

When you're looping through your matrix blocks, check against the block.type to see what kind of blocks you're dealing with. Assuming you find the block type that you want (at least once), try referencing the JS file with an includeJsFile tag...

{% includeJsFile "/your/site/script.js" %}

When you use that tag, your JS file will be queued up... If a future loop triggers the same tag, but the file is already queued up, it won't be added again.

Another benefit is that this will automatically render the script tag at the bottom of your page, just before the body tag closes.