Consider making more components callable

[frankieroberto]

It feels fairly common to include html (eg multiple paragraphs), and possibly even other components, with a Details component, or other components such as Panel or Inset Text.

To this end, it'd be nice to make these component callable, so you could do this:

{% call govukDetails({summaryText: 'Test'}) -%}
  <p>hello</p>
  <p>world</p>
{% endcall %}

as an alternative to this:

{% set detailsHtml %}
  <p>hello</p>
  <p>world</p>
{% endset %}

{% call govukDetails({summaryText: 'Test', html: detailsHtml}) -%}

[vanitabarrett]

This came up again today, suggested by a new user #2299

GDS components support passing HTML content inline or via a variable with separate set block. Often the structure of this content means that passing HTML content inline is messy or impossible. This results in many set blocks that are disconnected from their components, which is difficult to read.

A solution to this would be to support the caller() block within GDS macros. From Nunjucks documentation: A call block enables you to call a macro with all the text inside the tag. This is helpful if you want to pass a lot of content into a macro. The content is available inside the macro as caller().

[querkmachine]

Did some light investigation on this today. It does strike me as a weird omission, especially as implementing it would be a fairly simple, non-breaking enhancement.

I consider these to be good candidates for caller()-ification:

• Cookie banner: main content
• Details: main content
• Error summary: description HTML
• Inset text: main content
• Notification banner: main content
• Panel: main content
• Warning text: main content