我是一名业余学习使用node.js构建应用的人。我一直在跟随教程创建我的第一个node.js应用程序。一切都很顺利，直到我输入了“npm start”命令。日志显示：
C:\node\nodeteest3\bin\www:16
TypeError: undefined is not a function
at Object.<anonymous> M+<C;\node\nodetest3\bin\www:16:5
at Module_compile (module.js:460:26)
at Object.Module._extensions..js (module.js:478:10)
at Module.load (module.js:355:32)
at Function.Module._load (module.js:310:12)
at Function.module.runMain (module.js:501:10)
at startup(node.js:129:16)
at node.js:814:3
然后它输出了大约20行以“npm ERR！” +文件路径开头的内容，我认为这些内容不是必要的，因为错误似乎出现在二进制文件中。代码如下：
#!/usr/bin/env node
/**
* Module dependencies.
*/
var app = require('../app');
var debug = require('debug')('nodetest3:server');
var http = require('http');
/**
* Get port from environment and store in Express.
*/
var port = normalizePort(process.env.PORT || '3000');
这就是错误的指向位置：
[app.set('port', port);]
-------^在字母's'处的错误指针-所以设置明显-------------
app.set('port', port);
/**
* Create HTTP server.
*/
var server = http.createServer(app);
/**
* Listen on provided port, on all network interfaces.
*/
server.listen(port);
server.on('error', onError);
server.on('listening', onListening);
/**
* Normalize a port into a 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 for 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 with friendly messages
switch (error.code) {
case 'EACCES':
console.error(bind + ' requires elevated privileges');
process.exit(1);
break;
case 'EADDRINUSE':
console.error(bind + ' is already in use');
process.exit(1);
break;
default:
throw error;
}
}
/**
* Event listener for HTTP server "listening" event.
*/
function onListening() {
var addr = server.address();
var bind = typeof addr === 'string'
? 'pipe ' + addr
: 'port ' + addr.port;
debug('Listening on ' + bind);
}
Like I said in the beginning, I'm a complete beginner with command-line/github, but I'm already in love with it. I try to practice it every night after I finish my homework, and am getting really frustrated about getting stuck because I haven't been able to move forward for four days now. Also, I'm running this on node.js and the OS is Windows 8. Anything helps! Let me know if you want me to post any of the other code; I omitted so as to not add more than necessary.
"../app (app.js file) JUST 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 and forwarding to 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
// will 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 your 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 to user
app.use(function(err, req, res, next) {
res.status(err.status || 500);
res.render('error', {
message: err.message,
error: {}
});
});
app是从文件../app中获取的，请问该文件的内容是什么？请检查是否正确地在../app文件中使用了module.exports导出了 express 应用程序。看起来 node 并没有将app变量视为 express 应用程序的实例。 - Deepal