node.js获取本机内网与外网ip地址怎么实现？

var os = require('os');
function getLocalIP() {
    var map = [];
    var ifaces = os.networkInterfaces();
    console.log(ifaces);
    for (var dev in ifaces) {
        if (dev.indexOf('eth0') != -1) {
            var tokens = dev.split(':');
            var dev2 = null;
            if (tokens.length == 2) {
                dev2 = 'eth1:' + tokens[1];
            } else if (tokens.length == 1) {
                dev2 = 'eth1';
            }
            if (null == ifaces[dev2]) {
                continue;
            }
            // 找到eth0和eth1分别的ip
            var ip = null, ip2 = null;
            ifaces[dev].forEach(function(details) {
                if (details.family == 'IPv4') {
                    ip = details.address;
                }
            });
            ifaces[dev2].forEach(function(details) {
                if (details.family == 'IPv4') {
                    ip2 = details.address;
                }
            });
            if (null == ip || null == ip2) {
                continue;
            }
            // 将记录添加到map中去
            if (ip.indexOf('10.') == 0 ||
                ip.indexOf('172.') == 0 ||
                ip.indexOf('192.') == 0) {
                map.push({"intranet_ip" : ip, "internet_ip" : ip2});
            } else {
                map.push({"intranet_ip" : ip2, "internet_ip" : ip});
            }
        }
    } 
    return map;
}
console.log(getLocalIP());