isValidIPv4

1/**
2 * Checks if a string is a valid IPv4 address.
3 *
4 * @param ip - The IPv4 address to validate.
5 * @returns True if the input is a valid IPv4 address, false otherwise.
6 */
7export function isValidIPv4(ip: string): boolean {
8  const segments = ip.split('.');
9  if (segments.length !== 4) return false;
10
11  return segments.every(seg => {
12    if (!/^\d+$/.test(seg)) return false;
13    const num = Number(seg);
14    return num >= 0 && num <= 255 && String(num) === seg;
15  });
16}

1test('valid IPv4 addresses', () => {
2  expect(isValidIPv4('192.168.0.1')).toBe(true);
3  expect(isValidIPv4('0.0.0.0')).toBe(true);
4  expect(isValidIPv4('255.255.255.255')).toBe(true);
5});
6
7test('invalid IPv4 addresses - out of range', () => {
8  expect(isValidIPv4('256.100.50.25')).toBe(false);
9  expect(isValidIPv4('192.168.0.999')).toBe(false);
10});
11
12test('invalid IPv4 addresses - wrong segment count', () => {
13  expect(isValidIPv4('192.168.1')).toBe(false);
14  expect(isValidIPv4('10.0.0.1.2')).toBe(false);
15});
16
17test('invalid IPv4 addresses - non-numeric', () => {
18  expect(isValidIPv4('abc.def.ghi.jkl')).toBe(false);
19  expect(isValidIPv4('123.456.78.90a')).toBe(false);
20});
21
22test('invalid IPv4 addresses - leading zeroes', () => {
23  expect(isValidIPv4('01.02.03.04')).toBe(false);
24});