[Node.js]在windows下不得不防的小错误

TypeError: Arguments to path.join must be strings
at f (path.js:204:15)
at Object.filter (native)
at exports.join (path.js:209:40)
at exports.send (E:\nodejs\demo\socket.io-express\node_modules\express\node_modules\connect\lib\middleware\static.js:129:20)
at ServerResponse.res.sendfile (E:\nodejs\demo\socket.io-express\node_modules\express\lib\response.js:186:3)
at io.sockets.on.socket.emit.text (E:\nodejs\demo\socket.io-express\app.js:8:6)
at callbacks (E:\nodejs\demo\socket.io-express\node_modules\express\lib\router\index.js:272:11)
at param (E:\nodejs\demo\socket.io-express\node_modules\express\lib\router\index.js:246:11)
at pass (E:\nodejs\demo\socket.io-express\node_modules\express\lib\router\index.js:253:5)
at Router._dispatch (E:\nodejs\demo\socket.io- express\node_modules\express\lib\router\index.js:280:5)

var express = require('express');
var app = module.exports = express.createServer(),
io = require('socket.io').listen(app);

app.listen(3000);

app.get('/', function(req, res){
res.sendfile(__dirname + '/index.html');
});

io.sockets.on('connection', function(socket){
socket.emit('welcome', {text: 'OH HAI! U R CONNECTED!'});
});

var express = require('express');
var app = module.exports = express.createServer(),
io = require('socket.io').listen(app);
app.listen(3000);

app.get('/', function(req, res){
res.sendfile('/index.html', {root: __dirname});
});

io.sockets.on('connection', function(socket){
socket.emit('welcome', {text: 'OH HAI! U R CONNECTED'});
});