ip4ToInt, intToIp4, intToBin, isIp4InCidr, calculateCidrRange

ip4ToInt.js

const ip4ToInt = ip =>
  ip.split('.').reduce((int, oct) => (int << 8) + parseInt(oct, 10), 0) >>> 0;

const isIp4InCidr = ip => cidr => {
  const [range, bits = 32] = cidr.split('/');
  const mask = ~(2 ** (32 - bits) - 1);
  return (ip4ToInt(ip) & mask) === (ip4ToInt(range) & mask);
};

const isIp4InCidrs = (ip, cidrs) => cidrs.some(isIp4InCidr(ip));

// isIp4InCidrs('192.168.1.5', ['10.10.0.0/16', '192.168.1.1/24']); // true


const intToIp4 = int =>
  [(int >>> 24) & 0xFF, (int >>> 16) & 0xFF,
   (int >>> 8) & 0xFF, int & 0xFF].join('.');

const calculateCidrRange = cidr => {
  const [range, bits = 32] = cidr.split('/');
  const mask = ~(2 ** (32 - bits) - 1);
  return [intToIp4(ip4ToInt(range) & mask), intToIp4(ip4ToInt(range) | ~mask)];
};

calculateCidrRange('192.168.1.0/24'); // ["192.168.1.0", "192.168.1.255"]


const intToBin = int =>
  (int >>> 0).toString(2).padStart(32, 0).match(/.{1,8}/g).join('.');

intToBin(ip4ToInt('192.168.1.1')); // 11000000.10101000.00000001.00000001