How to use the markdown-it/lib/common/utils.unescapeAll function in markdown-it

start = pos,
      result = {
        ok: false,
        pos: 0,
        lines: 0,
        str: ''
      };

  if (str.charCodeAt(pos) === 0x3C /* < */) {
    pos++;
    while (pos < max) {
      code = str.charCodeAt(pos);
      if (code === 0x0A /* \n */) { return result; }
      if (code === 0x3E /* > */) {
        result.pos = pos + 1;
        result.str = unescapeAll(str.slice(start + 1, pos));
        result.ok = true;
        return result;
      }
      if (code === 0x5C /* \ */ && pos + 1 < max) {
        pos += 2;
        continue;
      }

      pos++;
    }

    // no closing '>'
    return result;
  }

  // this should be ... } else { ... branch

ok: false,
    pos: 0,
    lines: 0,
    str: ''
  };

  if (str.charCodeAt(pos) === 0x3C /* < */) {
      pos++;
      while (pos < max) {
        code = str.charCodeAt(pos);
        if (code === 0x0A /* \n */) {
            return result;
          }
        if (code === 0x3E /* > */) {
            result.pos = pos + 1;
            result.str = unescapeAll(str.slice(start + 1, pos));
            result.ok = true;
            return result;
          }
        if (code === 0x5C /* \ */ && pos + 1 < max) {
          pos += 2;
          continue;
        }

        pos++;
      }

      // no closing '>'
      return result;
    }

  // this should be ... } else { ... branch

md.renderer.rules.fence = function (tokens, idx, options) {
    const token = tokens[idx];
    const info = token.info ? unescapeAll(token.info).trim() : '';
    let langName = '';

    if (info) {
      langName = info.split(/\s+/g)[0];
      token.attrJoin('class', options.langPrefix + langName);
    }

    return render(token.content, langName);
  };
}