Correctly display page numbering (with and without total number of pages)

[DannySeidel]

I'm trying to add a variable to my template where the user can set a custom page numbering schema (DannySeidel/typst-dhbw-template#18). Due to the template using multiple different numbering styles, I want to enable the user to customize all sections.

I have a preface part that uses Roman numbering like this I. After that, the template shows the main part, which uses Latin numbering like this 1 / 1. Lastly, the template uses Latin letters for the appendix section like this a. Because the main section provides the total number of pages, I had to define a custom footer because the page counter does not provide the number of pages at a specific point in the document.

Currently, I create the footer as shown below:

  set page(footer: context align(
    numbering-alignment,
    numbering(
     "1 / 1",
      ..counter(page).get(),
      ..counter(page).at(<numbering-main-end>),
    ),
  ))

By using counter(page).at(<numbering-main-end>), I get the number of pages at this label. Because the user should be able to set the style for all three sections, I have now created labels at the end of all three sections. The problem is that if the user defines a style that does not contain the total number of pages, I still pass in the counter, and the number is still displayed. If I leave out the total count and the user defines a style with the total number of pages displayed, the total number of pages is shown as 1, as the data is missing.

How would I solve this problem? Maybe I could conditionally pass in the total number of pages only if it is needed? But how?

[DannySeidel]

Find the solution here https://forum.typst.app/t/how-to-correctly-display-page-numbering-in-a-custom-footer-with-and-without-total-number-of-pages/2021