How to check if a string is a valid IP address format in JavaScript ?
In this article, we will see how to check if a string is a valid IP address or not. An IP address is a unique identifier assigned to each device connected to a computer network that uses the Internet Protocol for communication. There are two common formats for IP addresses: IPv4 and IPv6. Checking if a string is a valid IP address format in JavaScript involves verifying if the string follows the rules for a standard IPv4 or IPv6 address.
These are the methods to check if a string is a valid IP address format in JavaScript:
Table of Content
- Using Split and Validate
- Using Library Functions
- Using net Module (Node.js specific):
- Using Built-in Methods:
Using Regular Expressions
This approach uses regular expressions to match valid IPv4 and IPv6 patterns.
Example: This example uses the Regular Expressions to validate the IP address format for the String.
function checkIpAddress(ip) {
const ipv4Pattern =
/^(\d{1,3}\.){3}\d{1,3}$/;
const ipv6Pattern =
/^([0-9a-fA-F]{1,4}:){7}[0-9a-fA-F]{1,4}$/;
return ipv4Pattern.test(ip) || ipv6Pattern.test(ip);
}
const ipAddress = "122.0.0.0";
console.log(checkIpAddress(ipAddress));
Output
true
Using Split and Validate
This approach splits the string by periods or colons and validates each part individually.
Example: This example describes the validation of IP address format for the string using Split and Validate.
function validIpAddress(ip) {
const parts = ip.split(/[.:]/);
if (parts.length === 4) {
// Check IPv4 parts
for (const part of parts) {
const num = parseInt(part);
if (isNaN(num) || num < 0 || num > 255) {
return false;
}
}
return true;
} else if (parts.length === 8) {
// Check IPv6 parts
for (const part of parts) {
if (!/^[0-9a-fA-F]{1,4}$/.test(part)) {
return false;
}
}
return true;
}
return false;
}
const ipAddress = "2001:0db8:85a3:0000:0000:8a2e:0370:7334";
console.log(validIpAddress(ipAddress));
Output
true
Using Library Functions
Some JavaScript libraries provide functions to validate IP addresses. One such library is ip-address, which offers comprehensive IP address validation capabilities.
- Install and use the ip-address library to validate IP addresses
const ip = require('ip-address');
Example: This example authenticating the validity of the IP address format of the String using the Library Functions.
const ip = require('ip-address');
function checkIpAdress(ipAddress) {
try {
const parsed = new ip.Address6(ipAddress);
return parsed.isValid() || new ip.Address4(ipAddress).isValid();
} catch (e) {
return false;
}
}
const ipAddress = "192.168.1.1";
console.log(checkIpAdress(ipAddress));
Output:
true
Using net Module (Node.js specific):
Node.js provides the net module, which can be utilized to validate IP addresses as well.
Example:
const net = require('net');
function isValidIpAddress(ipAddress) {
// For IPv4
if (net.isIPv4(ipAddress)) {
return true;
}
// For IPv6
if (net.isIPv6(ipAddress)) {
return true;
}
return false;
}
const ipAddress = "192.168.1.1";
console.log(isValidIpAddress(ipAddress));
Using Built-in Methods:
JavaScript’s built-in methods can also be utilized to check if a string is a valid IP address. One such method is inet_pton from the dns module. This method converts an IP address from its human-readable format (IPv4 or IPv6) into its binary form. By attempting to convert the string into binary format, we can determine if it’s a valid IP address.
Example:
const { promisify } = require('util');
const dns = require('dns');
// Promisify the dns.lookup method
const lookupPromise = promisify(dns.lookup);
// Function to check if a string is a valid IP address
async function isValidIPAddress(ipAddress) {
try {
// Attempt to convert the IP address to binary format
await lookupPromise(ipAddress);
return true; // If successful, it's a valid IP address
} catch (error) {
return false; // If an error occurs, it's not a valid IP address
}
}
// Example usage
const ipAddress = '192.168.0.1';
isValidIPAddress(ipAddress).then(result => {
console.log(result); // Output: true
});
Output:
true