function wrap(arr, sep, opts) {
  if (sep === '~') {
    sep = '-';
  }

  var str = arr.join(sep);
  var pre = opts && opts.regexPrefix; // regex logical `or`

  if (sep === '|') {
    str = pre ? pre + str : str;
    str = '(' + str + ')';
  } // regex character class


  if (sep === '-') {
    str = pre && pre === '^' ? pre + str : str;
    str = '[' + str + ']';
  }

  return [str];
}
Wrap the string with the correct regex
syntax.