public/scripts/util/showdown-patch.js

/**
 * Patches showdown to unrestrictedly unhash HTML spans.
 * @param {import('showdown')} showdown The showdown object to patch
 */
export function addShowdownPatch(showdown) {
    showdown.subParser('unhashHTMLSpans', function (text, options, globals) {
        'use strict';
        text = globals.converter._dispatch('unhashHTMLSpans.before', text, options, globals);

        for (var i = 0; i < globals.gHtmlSpans.length; ++i) {
            var repText = globals.gHtmlSpans[i],
                // limiter to prevent infinite loop (assume 10 as limit for recurse)
                limit = 0;

            while (/¨C(\d+)C/.test(repText)) {
                var num = RegExp.$1;
                repText = repText.replace('¨C' + num + 'C', globals.gHtmlSpans[num]);
                if (limit === 10000) {
                    console.error('maximum nesting of 10000 spans reached!!!');
                    break;
                }
                ++limit;
            }
            text = text.replace('¨C' + i + 'C', repText);
        }

        text = globals.converter._dispatch('unhashHTMLSpans.after', text, options, globals);
        return text;
    });
}