node.js - TypeError:无法读取未定义的属性“PORT”

Question

As I type -- 

node server

I get the error as given in the title after these lines:

E:\Nodejs_chat_app\server.js:7
var port = Number(process.evn.PORT) || 3000;

以下是在server.js文件中编写的代码段-

var express = require('express');
var app = express();
var server = require('http').createServer(app);
var io = require('socket.io').listen(server);
users = [];
connections = [];
var port = Number(process.evn.PORT) || 8888;
server.listen(port);
console.log('server running');

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

     有人可以告诉我这个错误。我是新手吗？

Answer 1

有一个错字，应该是：process.env.PORT，而不是process.evn.PORT。