Load Block-Specific Assets - modmore documentation

Some blocks need a large script or stylesheet, such as Prism for a code block. Load those files only when that block is on the page.

cbHasField checks the canvas for a block key. blocks/code.json has the key code. blocks/structure/heading.json has the key structure/heading.

Call it cached. Pass &resource when the check is for a different page. Unpublished blocks, and blocks outside their publish window, do not count.

Example

Assume Prism is at /assets/css/prism.css and /assets/js/prism.js, and the code block key is code.

Template head:

[[cbHasField?
    &block=`code`
    &then=`<link rel="stylesheet" href="/assets/css/prism.css">`
]]

Template footer:

[[cbHasField?
    &block=`code`
    &then=`<script src="/assets/js/prism.js"></script>`
]]

&field is the same property as &block. The files are included only when that page has a live code block.

To return a chunk name from &then or &else, return the name only and wrap the snippet call in a chunk tag:

[[$[[cbHasField? &field=`code` &then=`prism_assets`]]]]

Putting [[$prism_assets]] directly in &then parses that chunk before the condition runs.