Snippets/Auto-number headings

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Auto-number headings
Language(s):	JavaScript , CSS
Compatible with:	MediaWiki 1.37+ (vector)

Description

Replace the "Auto-number headings" feature that previously existed in MediaWiki core (T284921).

This can be registered as a gadget on any wiki by copying the below code to MediaWiki:Gadget-autonum.js and MediaWiki:Gadget-autonum.css respectively, and adding the following to "MediaWiki:Gadgets-definition":

* autonum[ResourceLoader]|autonum.css|autonum.js

Code

JS

/**
 * Auto-number headings
 *
 * @source https://www.mediawiki.org/wiki/Snippets/Auto-number_headings
 * @author Krinkle
 * @version 2021-10-03
 */
var toc = document.querySelector('#toc');
if (toc) {
  document.querySelectorAll('.mw-parser-output :is(h1,h2,h3,h4,h5,h6) .mw-headline').forEach(function (headline) {
    var num = toc.querySelector('a[href="#' + CSS.escape(headline.id) + '"] .tocnumber');
    if (num) headline.prepend(num.textContent + ' ');
  });
} else {
  document.body.classList.add('tpl-autonum');
}

CSS

/**
 * Auto-number headings
 *
 * @source https://www.mediawiki.org/wiki/Snippets/Auto-number_headings
 * @author Krinkle
 * @version 2021-10-03
 */
/**
 * Fallback for pages without a TOC. This could in principle work for all pages,
 * but we don't to ensure consistency between the TOC and heading numbers 
 */
.tpl-autonum .mw-parser-output {
  counter-reset: autonum-h2 autonum-h3 autonum-h4 autonum-h5 autonum-h6;
}
.tpl-autonum .mw-parser-output h2 {
  counter-reset: autonum-h3 autonum-h4 autonum-h5 autonum-h6;
}
.tpl-autonum .mw-parser-output h3 {
  counter-reset: autonum-h4 autonum-h5 autonum-h6;
}
.tpl-autonum .mw-parser-output h4 {
  counter-reset: autonum-h5 autonum-h6;
}
.tpl-autonum .mw-parser-output h5 {
  counter-reset: autonum-h6;
}
.tpl-autonum .mw-parser-output h2 .mw-headline:before {
  counter-increment: autonum-h2;
  content: counter(autonum-h2) " ";
}
.tpl-autonum .mw-parser-output h3 .mw-headline:before {
  counter-increment: autonum-h3;
  content: counter(autonum-h2) "." counter(autonum-h3) " ";
}
.tpl-autonum .mw-parser-output h4 .mw-headline:before {
  counter-increment: autonum-h4;
  content: counter(autonum-h2) "." counter(autonum-h3) "." counter(autonum-h4) " ";
}
.tpl-autonum .mw-parser-output h5 .mw-headline:before {
  counter-increment: autonum-h5;
  content: counter(autonum-h2) "." counter(autonum-h3) "." counter(autonum-h4) "." counter(autonum-h5) " ";
}
.tpl-autonum .mw-parser-output h6 .mw-headline:before {
  counter-increment: autonum-h6;
  content: counter(autonum-h2) "." counter(autonum-h3) "." counter(autonum-h4) "." counter(autonum-h5) "." counter(autonum-h6) " ";
}