isIP.js

import assertString from './util/assertString';
/**
11.3.  Examples

   The following addresses

             fe80::1234 (on the 1st link of the node)
             ff02::5678 (on the 5th link of the node)
             ff08::9abc (on the 10th organization of the node)

   would be represented as follows:

             fe80::1234%1
             ff02::5678%5
             ff08::9abc%10

   (Here we assume a natural translation from a zone index to the
   <zone_id> part, where the Nth zone of any scope is translated into
   "N".)

   If we use interface names as <zone_id>, those addresses could also be
   represented as follows:

            fe80::1234%ne0
            ff02::5678%pvc1.3
            ff08::9abc%interface10

   where the interface "ne0" belongs to the 1st link, "pvc1.3" belongs
   to the 5th link, and "interface10" belongs to the 10th organization.
 * * */
const IPv4SegmentFormat = '(?:[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])';
const IPv4AddressFormat = `(${IPv4SegmentFormat}[.]){3}${IPv4SegmentFormat}`;
const IPv4AddressRegExp = new RegExp(`^${IPv4AddressFormat}$`);

const IPv6SegmentFormat = '(?:[0-9a-fA-F]{1,4})';
const IPv6AddressRegExp = new RegExp('^(' +
  `(?:${IPv6SegmentFormat}:){7}(?:${IPv6SegmentFormat}|:)|` +
  `(?:${IPv6SegmentFormat}:){6}(?:${IPv4AddressFormat}|:${IPv6SegmentFormat}|:)|` +
  `(?:${IPv6SegmentFormat}:){5}(?::${IPv4AddressFormat}|(:${IPv6SegmentFormat}){1,2}|:)|` +
  `(?:${IPv6SegmentFormat}:){4}(?:(:${IPv6SegmentFormat}){0,1}:${IPv4AddressFormat}|(:${IPv6SegmentFormat}){1,3}|:)|` +
  `(?:${IPv6SegmentFormat}:){3}(?:(:${IPv6SegmentFormat}){0,2}:${IPv4AddressFormat}|(:${IPv6SegmentFormat}){1,4}|:)|` +
  `(?:${IPv6SegmentFormat}:){2}(?:(:${IPv6SegmentFormat}){0,3}:${IPv4AddressFormat}|(:${IPv6SegmentFormat}){1,5}|:)|` +
  `(?:${IPv6SegmentFormat}:){1}(?:(:${IPv6SegmentFormat}){0,4}:${IPv4AddressFormat}|(:${IPv6SegmentFormat}){1,6}|:)|` +
  `(?::((?::${IPv6SegmentFormat}){0,5}:${IPv4AddressFormat}|(?::${IPv6SegmentFormat}){1,7}|:))` +
  ')(%[0-9a-zA-Z-.:]{1,})?$');

export default function isIP(ipAddress, options = {}) {
  assertString(ipAddress);

  // accessing 'arguments' for backwards compatibility: isIP(ipAddress [, version])
  // eslint-disable-next-line prefer-rest-params
  const version = (typeof options === 'object' ? options.version : arguments[1]) || '';

  if (!version) {
    return isIP(ipAddress, { version: 4 }) || isIP(ipAddress, { version: 6 });
  }

  if (version.toString() === '4') {
    return IPv4AddressRegExp.test(ipAddress);
  }

  if (version.toString() === '6') {
    return IPv6AddressRegExp.test(ipAddress);
  }

  return false;
}