以下是jhurliman回答的多ip地址版本:

function getIPAddresses() {

    var ipAddresses = [];

    var interfaces = require('os').networkInterfaces();
    for (var devName in interfaces) {
        var iface = interfaces[devName];
        for (var i = 0; i < iface.length; i++) {
            var alias = iface[i];
            if (alias.family === 'IPv4' && alias.address !== '127.0.0.1' && !alias.internal) {
                ipAddresses.push(alias.address);
            }
        }
    }
    return ipAddresses;
}

调用ifconfig是非常依赖于平台的，而且网络层知道套接字所在的IP地址，所以最好是询问它。

Node.js并没有公开这样做的直接方法，但是你可以打开任何套接字，并询问正在使用的本地IP地址。例如，打开www.google.com的套接字:

var net = require('net');
function getNetworkIP(callback) {
  var socket = net.createConnection(80, 'www.google.com');
  socket.on('connect', function() {
    callback(undefined, socket.address().address);
    socket.end();
  });
  socket.on('error', function(e) {
    callback(e, 'error');
  });
}

使用情况:

getNetworkIP(function (error, ip) {
    console.log(ip);
    if (error) {
        console.log('error:', error);
    }
});

下面是一个允许你获取本地IP地址的变体(在Mac和Windows上测试):

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); // 10.25.10.147

这里有一个简洁的小命令行，它实现了这个功能:

const ni = require('os').networkInterfaces();
Object
  .keys(ni)
  .map(interf =>
    ni[interf].map(o => !o.internal && o.family === 'IPv4' && o.address))
  .reduce((a, b) => a.concat(b))
  .filter(o => o)
  [0];

使用内部ip:

const internalIp = require("internal-ip")

console.log(internalIp.v4.sync())

下面是一段Node.js代码，它将解析ifconfig的输出并(异步地)返回找到的第一个IP地址:

(它只在Mac OS X v10.6 (Snow Leopard)上测试;我希望它也能在Linux上运行。)

var getNetworkIP = (function () {
    var ignoreRE = /^(127\.0\.0\.1|::1|fe80(:1)?::1(%.*)?)$/i;

    var exec = require('child_process').exec;
    var cached;
    var command;
    var filterRE;

    switch (process.platform) {
        // TODO: implement for OSes without the ifconfig command
        case 'darwin':
             command = 'ifconfig';
             filterRE = /\binet\s+([^\s]+)/g;
             // filterRE = /\binet6\s+([^\s]+)/g; // IPv6
             break;
        default:
             command = 'ifconfig';
             filterRE = /\binet\b[^:]+:\s*([^\s]+)/g;
             // filterRE = /\binet6[^:]+:\s*([^\s]+)/g; // IPv6
             break;
    }

    return function (callback, bypassCache) {
        // Get cached value
        if (cached && !bypassCache) {
            callback(null, cached);
            return;
        }

        // System call
        exec(command, function (error, stdout, sterr) {
            var ips = [];
            // Extract IP addresses
            var matches = stdout.match(filterRE);

            // JavaScript doesn't have any lookbehind regular expressions, so we need a trick
            for (var i = 0; i < matches.length; i++) {
                ips.push(matches[i].replace(filterRE, '$1'));
            }

            // Filter BS
            for (var i = 0, l = ips.length; i < l; i++) {
                if (!ignoreRE.test(ips[i])) {
                    //if (!error) {
                        cached = ips[i];
                    //}
                    callback(error, ips[i]);
                    return;
                }
            }
            // Nothing found
            callback(error, null);
        });
    };
})();

使用的例子:

getNetworkIP(function (error, ip) {
    console.log(ip);
    if (error) {
        console.log('error:', error);
    }
}, false);

如果第二个参数为true，函数将每次执行一次系统调用;否则使用缓存的值。

更新版本

返回所有本地网络地址的数组。

在Ubuntu 11.04 (Natty Narwhal)和Windows XP 32上测试

var getNetworkIPs = (function () {
    var ignoreRE = /^(127\.0\.0\.1|::1|fe80(:1)?::1(%.*)?)$/i;

    var exec = require('child_process').exec;
    var cached;
    var command;
    var filterRE;

    switch (process.platform) {
        case 'win32':
        //case 'win64': // TODO: test
            command = 'ipconfig';
            filterRE = /\bIPv[46][^:\r\n]+:\s*([^\s]+)/g;
            break;
        case 'darwin':
            command = 'ifconfig';
            filterRE = /\binet\s+([^\s]+)/g;
            // filterRE = /\binet6\s+([^\s]+)/g; // IPv6
            break;
        default:
            command = 'ifconfig';
            filterRE = /\binet\b[^:]+:\s*([^\s]+)/g;
            // filterRE = /\binet6[^:]+:\s*([^\s]+)/g; // IPv6
            break;
    }

    return function (callback, bypassCache) {
        if (cached && !bypassCache) {
            callback(null, cached);
            return;
        }

        // System call
        exec(command, function (error, stdout, sterr) {
            cached = [];
            var ip;
            var matches = stdout.match(filterRE) || [];
            //if (!error) {
            for (var i = 0; i < matches.length; i++) {
                ip = matches[i].replace(filterRE, '$1')
                if (!ignoreRE.test(ip)) {
                    cached.push(ip);
                }
            }
            //}
            callback(error, cached);
        });
    };
})();

使用举例:升级版本

getNetworkIPs(function (error, ip) {
console.log(ip);
if (error) {
    console.log('error:', error);
}
}, false);