@photogabble/eleventy-plugin-interlinker/src/markdown-ext.js

Obsidian WikiLinks, BackLinks and Embed support for 11ty

/**
 * This rule will be looped through an inline token by markdown-it.
 *
 * @param {WikilinkParser} wikilinkParser
 * @returns {(function(*, *): (boolean|undefined))|*}
 */
export const wikilinkInlineRule = (wikilinkParser) => (state, silent) => {
  // Have we found the start of a WikiLink Embed `![[`
  if (state.src.charAt(state.pos) === '[' && state.src.charAt(state.pos + 1) !== '[') return false; // Not wikilink opening
  if (state.src.charAt(state.pos) === '!' && state.src.substring(state.pos, state.pos + 3) !== '![[') return false; // Not embed opening

  const matches = state.src.match(wikilinkParser.wikiLinkRegExp);
  if (!matches) return false;

  // We have found the start of a WikiLink (`[[`) or Embed (`![[`)
  // char at state.pos will be either `[` or `!`, need to walk through state.src until `]]` is encountered
  let pos = state.pos;
  let text = '';
  let found = false;
  while (pos <= state.posMax) {
    text += state.src.charAt(pos);
    if (text.length > 2 && text.substring(text.length - 2) === ']]') {
      found = true;
      break;
    }
    pos++;
  }

  if (!found) return false;

  const wikiLink = wikilinkParser.linkCache.get(text);

  // By this time in the execution cycle the wikilink parser's cache should contain all
  // wikilinks, including those linking to a stub. In the unlikely case that it doesn't
  // we ignore the wikilink.
  if (!wikiLink) return false;

  if (!silent) {
    // The wikilink content is HTML generated by a "Resolving Function" lets make use of
    // the builtin html_inline render rule to display it.
    const token = state.push('html_inline', '', 0);
    token.content = wikiLink.content.trim();
  }

  state.pos = state.pos + text.length;
  return true;
};

/**
 * This rule is to catch Wikilink Embeds that are bookended by new lines e.g `\n![[test]]\n`, the inline rule
 * would only get the content within the new lines with the newlines themselves getting tokenised as a paragraph.
 * That was causing the bugs raised in issues #65 and #66.
 *
 * @param wikilinkParser
 * @return {(function(*, *, *, *): boolean)|*}
 */
export const wikilinkBlockRule = (wikilinkParser) => (state, startLine, endLine, silent) => {
  let pos = state.bMarks[startLine] + state.tShift[startLine]
  let max = state.eMarks[startLine]

  // if it's indented more than 3 spaces, it should be a code block
  if (state.sCount[startLine] - state.blkIndent >= 4) { return false }

  // This block rule only cares about Wiki Link embeds that are at a block level (on a single line bookended by `\n`)
  // therefore if the line text doesn't begin with `![[` we do not continue.
  let lineText = state.src.slice(pos, max);
  if (lineText.substring(0, 3) !== '![[') return false;

  const wikiLink = wikilinkParser.linkCache.get(lineText);
  if (!wikiLink) return false;

  if (!silent) {
    const token = state.push('html_block', '', 0);
    token.content = wikiLink.content.trim();
  }

  // Block level Wikilink embeds should be on a single line, increment the line counter and continue.
  state.line++;

  return true;
};

export const install = (md, wikilinkParser) => {
  md.inline.ruler.push('inline_wikilink', wikilinkInlineRule(
    wikilinkParser,
  ));

  md.block.ruler.before('heading', 'block_wikilink', wikilinkBlockRule(
    wikilinkParser,
  ), {
    // alt contains a list of rules which can be terminated by this one
    alt: ['paragraph', 'reference', 'blockquote']
  });
}