Get local external ip address with nodejs

ip.js

var
    // Local ip address that we're trying to calculate
    address
    // Provides a few basic operating-system related utility functions (built-in)
    ,os = require('os')
    // Network interfaces
    ,ifaces = os.networkInterfaces();


// Iterate over interfaces ...
for (var dev in ifaces) {

    // ... and find the one that matches the criteria
    var iface = ifaces[dev].filter(function(details) {
        return details.family === 'IPv4' && details.internal === false;
    });

    if(iface.length > 0) address = iface[0].address;
}

// Print the result
console.log(address);

My TypeScript version of the functions to get internal and external IPv4 network interface infos (NInfos):

// commonjs: const { networkInterfaces } = require('os')
import { networkInterfaces, NetworkInterfaceInfo } from 'os';

/**
 * Returns an array of `NetworkInterfaceInfo`s for all host interfaces that
 * have IPv4 addresses from the private address space,
 * including the loopback address space (127.x.x.x).
 */
export const getPrivateIPNInfos = (): (NetworkInterfaceInfo | undefined)[] => {
  return Object.values(networkInterfaces())
    .flatMap((infos) => {
      return infos?.filter((i) => i.family === 'IPv4');
    })
    .filter((info) => {
      return (
        info?.address.match(
          /(^127\.)|(^10\.)|(^172\.1[6-9]\.)|(^172\.2[0-9]\.)|(^172\.3[0-1]\.)|(^192\.168\.)/
        ) !== null
      );
    });
};

/**
 * Returns an array of IPv4 addresses for all host interfaces that
 * have IPv4 addresses from the private address space,
 * including the loopback address space (127.x.x.x).
 */
export const getPrivateIPs = (): (string | undefined)[] => {
  return getPrivateIPNInfos().map((i) => i?.address);
};


/**
 * Returns an array of `NetworkInterfaceInfo`s for all host interfaces that
 * have IPv4 addresses from the external private address space,
 * ie. except the loopback (internal) address space (127.x.x.x).
 */
export const getPrivateExternalIPNInfos = (): (
  | NetworkInterfaceInfo
  | undefined
)[] => {
  return Object.values(networkInterfaces())
    .flatMap((infos) => {
      return infos?.filter((i) => !i.internal && i.family === 'IPv4');
    })
    .filter((info) => {
      return (
        info?.address.match(
          /(^10\.)|(^172\.1[6-9]\.)|(^172\.2[0-9]\.)|(^172\.3[0-1]\.)|(^192\.168\.)/
        ) !== null
      );
    });
};

/**
 * Returns an array of IPv4 addresses for all host interfaces that
 * have IPv4 addresses from the external private address space,
 * ie. except the loopback (internal) address space (127.x.x.x).
 */
export const getPrivateExternalIPs = (): (string | undefined)[] => {
  return getPrivateExternalIPNInfos().map((i) => i?.address);
};

Sample output:

[
  {
    address: '127.0.0.1',
    netmask: '255.0.0.0',
    family: 'IPv4',
    mac: '00:00:00:00:00:00',
    internal: true,
    cidr: '127.0.0.1/8'
  }
]

[
  {
    address: '192.168.88.176',
    netmask: '255.255.255.0',
    family: 'IPv4',
    mac: 'xx:xx:xx:xx:xx:xx',
    internal: false,
    cidr: '192.168.88.176/24'
  }
]

The other functions just return the addresses directly.

...Oh, yeah, the naming of the functions happened by accident, but I decided to keep them.

Even more condensed with find and flat.

import { networkInterfaces } from 'os';

const ip = Object.values(networkInterfaces()).flat().find(i => i.family == 'IPv4' && !i.internal).address;

Thanks, it worked !! Optimized it further as:

const ip = Object.values(require('os').networkInterfaces()).flat().find(i => i.family == 'IPv4' && !i.internal).address;

Thanks, it worked !! Optimized it further as:

const ip = Object.values(require('os').networkInterfaces()).flat().find(i => i.family == 'IPv4' && !i.internal).address;

I'm sorry Rajat but making code less readable is not an optimization. 😉

Even more condensed with find and flat.

import { networkInterfaces } from 'os';

const ip = Object.values(networkInterfaces()).flat().find(i => i.family == 'IPv4' && !i.internal).address;

Typescript version (added optional chaining):

import { networkInterfaces } from 'os';

const ip = Object.values(networkInterfaces()).flat().find((i) => i?.family === 'IPv4' && !i?.internal)?.address;

thank all of you so much