markdown-it/lib/rules_inline/backticks.mjs

// Parse backticks

export default function backtick(state, silent) {
  var start, max, marker, token, matchStart, matchEnd, openerLength, closerLength,
      pos = state.pos,
      ch = state.src.charCodeAt(pos);

  if (ch !== 0x60/* ` */) { return false; }

  start = pos;
  pos++;
  max = state.posMax;

  // scan marker length
  while (pos < max && state.src.charCodeAt(pos) === 0x60/* ` */) { pos++; }

  marker = state.src.slice(start, pos);
  openerLength = marker.length;

  if (state.backticksScanned && (state.backticks[openerLength] || 0) <= start) {
    if (!silent) state.pending += marker;
    state.pos += openerLength;
    return true;
  }

  matchEnd = pos;

  // Nothing found in the cache, scan until the end of the line (or until marker is found)
  while ((matchStart = state.src.indexOf('`', matchEnd)) !== -1) {
    matchEnd = matchStart + 1;

    // scan marker length
    while (matchEnd < max && state.src.charCodeAt(matchEnd) === 0x60/* ` */) { matchEnd++; }

    closerLength = matchEnd - matchStart;

    if (closerLength === openerLength) {
      // Found matching closer length.
      if (!silent) {
        token     = state.push('code_inline', 'code', 0);
        token.markup  = marker;
        token.content = state.src.slice(pos, matchStart)
          .replace(/\n/g, ' ')
          .replace(/^ (.+) $/, '$1');
      }
      state.pos = matchEnd;
      return true;
    }

    // Some different length found, put it in cache as upper limit of where closer can be found
    state.backticks[closerLength] = matchStart;
  }

  // Scanned through the end, didn't find anything
  state.backticksScanned = true;

  if (!silent) state.pending += marker;
  state.pos += openerLength;
  return true;
}