solutions/0468-validate-ip-address.js

/**
 * 468. Validate IP Address
 * https://leetcode.com/problems/validate-ip-address/
 * Difficulty: Medium
 *
 * Given a string queryIP, return "IPv4" if IP is a valid IPv4 address, "IPv6" if IP is a valid
 * IPv6 address or "Neither" if IP is not a correct IP of any type.
 *
 * A valid IPv4 address is an IP in the form "x1.x2.x3.x4" where 0 <= xi <= 255 and xi cannot
 * contain leading zeros. For example, "192.168.1.1" and "192.168.1.0" are valid IPv4 addresses
 * while "192.168.01.1", "192.168.1.00", and "192.168@1.1" are invalid IPv4 addresses.
 *
 * A valid IPv6 address is an IP in the form "x1:x2:x3:x4:x5:x6:x7:x8" where:
 * - 1 <= xi.length <= 4
 * - xi is a hexadecimal string which may contain digits, lowercase English letter ('a' to 'f')
 *   and upper-case English letters ('A' to 'F').
 * - Leading zeros are allowed in xi.
 *
 * For example, "2001:0db8:85a3:0000:0000:8a2e:0370:7334" and "2001:db8:85a3:0:0:8A2E:0370:7334"
 * are valid IPv6 addresses, while "2001:0db8:85a3::8A2E:037j:7334" and
 * "02001:0db8:85a3:0000:0000:8a2e:0370:7334" are invalid IPv6 addresses.
 */

/**
 * @param {string} queryIP
 * @return {string}
 */
var validIPAddress = function(queryIP) {
  const ipv4 = /^((\d|[1-9]\d|1\d\d|2[0-4]\d|25[0-5])\.){3}(\d|[1-9]\d|1\d\d|2[0-4]\d|25[0-5])$/;
  const ipv6 = /^([\da-fA-F]{1,4}:){7}[\da-fA-F]{1,4}$/;

  return ipv4.test(queryIP) ? 'IPv4' : ipv6.test(queryIP) ? 'IPv6' : 'Neither';
};