Node.js. Get server IPs (v4) information (WAN/LAN IPs).

ip-info.ts

/*
    Server IP Information Utils
    by VILIC VANE <https://github.com/vilic>
    MIT License
*/

import * as OS from 'os';

export interface IPInfo {
    lanIP: string;
    wanIP: string;
}

export function getIPInfo(): IPInfo {
    let interfacesMap = OS.networkInterfaces();
    
    let lanIP: string;
    let wanIP: string;
    
    outer:
    for (let deviceName of Object.keys(interfacesMap)) {
        let interfaces = interfacesMap[deviceName];
        for (let interface of interfaces) {
            if (
                interface.internal ||
                interface.family != 'IPv4' ||
                interface.mac == '00:00:00:00:00:00' ||
                /^169\.254\./.test(interface.address)
            ) {
                continue;
            }
            
            let address = interface.address;
            let numbers = address
                .split('.')
                .map(n => Number(n));
            
            if (
                numbers[0] == 10 ||
                (numbers[0] == 172 && (numbers[1] >> 4) == 1) ||
                (numbers[0] == 192 && numbers[1] == 168)
            ) {
                if (!lanIP) {
                    lanIP = address;
                    
                    if (wanIP) {
                        break outer;
                    }
                }
            } else {
                if (!wanIP) {
                    wanIP = address;
                    
                    if (lanIP) {
                        break outer;
                    }
                }
            }
        }
    }
    
    if (!wanIP) {
        // for test purpose.
        wanIP = lanIP;
    }
    
    return { lanIP, wanIP };
}