Node.js参考错误：索引未定义

Question

I am building a chat application, and this index.js file is in the "routes" directory. The error is on the first line. There is also an index.jade file in the "views" directory.

module.exports.index = index;
module.exports.logon = logon;
module.exports.message = message;

exports.index = function index(req, res){
  res.render('index');
};

function logon(req, res){
  res.send('Logon');
};

function message(req, res){
  res.send('Message');
};

Answer 1

You are doing exports two times, also there is no variable index .

exports.index = function index(req, res){
  res.render('index');
};

module.exports.index = index;

try using

module.exports.index = index;

var index = function(req,res) {
  res.render('index');
}

Answer 2

When you assign a function to a variable, or you immediately call a function, you turn it from a statement into an expression. This causes function hoisting to not happen. You can fix the issue by not assigning the function index to exports.index , to restore the hoisting behavior:

function index(req, res){
  res.render('index');
};

You'll still have problem after that, because logon and message are not defined (you've defined login and chat instead).