src/utils/text/skip-newline.js/skipNewline
function skipNewline(text, index, opts) {
  const backwards = opts && opts.backwards;
  if (index === false) {
    return false;
  }

  const atIndex = text.charAt(index);
  if (backwards) {
    // We already replace `\r\n` with `\n` before parsing
    /* istanbul ignore next */
    if (text.charAt(index - 1) === "\r" && atIndex === "\n") {
      return index - 2;
    }
    if (
      atIndex === "\n" ||
      atIndex === "\r" ||
      atIndex === "\u2028" ||
      atIndex === "\u2029"
    ) {
      return index - 1;
    }
  } else {
    // We already replace `\r\n` with `\n` before parsing
    /* istanbul ignore next */
    if (atIndex === "\r" && text.charAt(index + 1) === "\n") {
      return index + 2;
    }
    if (
      atIndex === "\n" ||
      atIndex === "\r" ||
      atIndex === "\u2028" ||
      atIndex === "\u2029"
    ) {
      return index + 1;
    }
  }

  return index;
}