javascript - app.set('port', port) 'TypeError: undefined is not a function'. Beginner, need ideas -

i'm amateur learning build node.js. i've been following tutorial create first node.js app. worked until entered 'npm start'. log is:

c:\node\nodeteest3\bin\www:16 typeerror: undefined not function     @ object.<anonymous> m+<c;\node\nodetest3\bin\www:16:5     @ module_compile (module.js:460:26)     @ object.module._extensions..js (module.js:478:10)     @ module.load (module.js:355:32)     @ function.module._load (module.js:310:12)     @ function.module.runmain (module.js:501:10)     @ startup(node.js:129:16)     @ node.js:814:3 

then output 20 lines starting "npm err! " + filepaths, don't think necessary, error seems in bin file. code is

#!/usr/bin/env node /** * module dependencies. */  var app = require('../app'); var debug = require('debug')('nodetest3:server'); var http = require('http');  /** * port environment , store in express.  */  var port = normalizeport(process.env.port || '3000'); 

this error points to:

[app.set('port', port);] 

-------^error pointer @ 's'-so set------------

app.set('port', port);  /**  * create http server.  */  var server = http.createserver(app);   /**  * listen on provided port, on network interfaces.  */  server.listen(port); server.on('error', onerror); server.on('listening', onlistening);   /**  * normalize port number, string, or false.  */  function normalizeport(val) {     var port = parseint(val, 10);    if (isnan(port)) {     // named pipe     return val;   }    if (port >= 0) {     // port number     return port;    }     return false; }  /** * event listener http server "error" event. */  function onerror(error) {   if (error.syscall !== 'listen') {     throw error;   }    var bind = typeof port === 'string'     ? 'pipe ' + port     : 'port ' + port;    // handle specific listen errors friendly messages   switch (error.code) {     case 'eacces':       console.error(bind + ' requires elevated privileges');       process.exit(1);       break;     case 'eaddrinuse':       console.error(bind + ' in use');       process.exit(1);       break;     default:       throw error;   } }  /**  * event listener http server "listening" event.  */  function onlistening() {   var addr = server.address();   var bind = typeof addr === 'string'     ? 'pipe ' + addr     : 'port ' + addr.port;   debug('listening on ' + bind); }  said in beginning, i'm complete beginner command-line/github, i'm in love it. try practice every night after finish homework, , getting frustrated getting stuck because haven't been able move forward 4 days now. also, i'm running on node.js , os windows 8. helps!  let me know if want me post of other code; omitted not add more necessary.   "../app (app.js file) added"*************************** ../app file:     [ app.js   ]  var express = require('express');  var path = require('path');  var favicon = require('serve-favicon');  var logger = require('morgan');  var cookieparser = require('cookie-parser');  var bodyparser = require('body-parser');   var routes = require('./routes/index'); var users = require('./routes/users'); var app = express();  ///  catch 404 , forwarding error handler app.use(function(req, res, next) {     var err = new error('not found');     err.status = 404;     next(err); }); var app = express(); // error handlers  // development error handler // print stacktrace if (app.get('env') === 'development') {         app.use(function(err, req, res, next) {         res.status(err.status || 500);         res.render('error', {             message: err.message,             error: err         });     }); }   var app = express();   // view engine setup app.set('views', path.join(__dirname, 'views')); app.set('view engine', 'jade');  // uncomment after placing favicon in /public //app.use(favicon(__dirname + '/public/favicon.ico')); app.use(logger('dev')); app.use(bodyparser.json({estended: true})); app.use(bodyparser.urlencoded({extended: true})); app.use(cookieparser({extended:true})); app.use(express.static(path.join(__dirname, 'public')));  app.use('/', routes); app.use('/users', users);      //  production error handler // no stacktraces leaked user app.use(function(err, req, res, next) {     res.status(err.status || 500);     res.render('error', {         message: err.message,         error: {}     }); }); 

you not exporting in app.js file. @ end of app.js file, include following line.

module.exports = app; 

see whether problem goes away.

and 1 more addition: have var app = express(); twice in app.js.