Nertivia-Client/src/utils/markdown-it-plugins/normalizeFence.js

function fence(state, startLine, endLine, silent) {
  var marker, len, params, nextLine, mem, token, markup,
      haveEndMarker = false,
      pos = state.bMarks[startLine] + state.tShift[startLine],
      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; }

  if (pos + 3 > max) { return false; }

  marker = state.src.charCodeAt(pos);

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

  // scan marker length
  let count = state.skipChars(pos, marker);

  len = count - pos;
  pos += 3

  if (len < 3) { return false; }

  markup = state.src.slice(mem, pos);
  params = state.src.slice(pos, max);

  if (marker === 0x60 /* ` */) {
    if (params.indexOf(String.fromCharCode(marker)) >= 0) {
      return false;
    }
  }

  // Since start is found, we can report success here in validation mode
  if (silent) { return true; }

  // search end of block
  nextLine = startLine;

  for (;;) {
    nextLine++;
    if (nextLine >= endLine) {
      return false
    }

    pos = mem = state.bMarks[nextLine] + state.tShift[nextLine];
    max = state.eMarks[nextLine];

    if (state.src.charCodeAt(pos) !== marker) { continue; }

    pos = state.skipChars(pos, marker);

    // closing code fence must be at least as long as the opening one
    if (pos - mem < 3) { continue; }

    // make sure tail has spaces only
    pos = state.skipSpaces(pos);

    if (pos < max) { continue; }

    haveEndMarker = true;
    // found!
    break;
  }

  // If a fence has heading spaces, they should be removed from its inner block
  len = state.sCount[startLine];

  state.line = nextLine + (haveEndMarker ? 1 : 0);

  token         = state.push('fence', 'code', 0);
  token.info    = params;
  token.content = state.getLines(startLine + 1, nextLine, len, true);
  token.markup  = markup;
  token.map     = [ startLine, state.line ];

  return true;
}

export default function normalizeFence(md, opts) {
  md.block.ruler.at('fence', fence, {alt: [ 'paragraph', 'reference', 'blockquote', 'list' ]})
}