Question

我得到一个module.js：339 throw err;

我不确定哪条线或哪个地方需要修理它。如果我能指出正确的方向，我想我会解决它。我正在搜索错误的信息，我似乎无法弄清楚为什么以及如何以及如何解决错误。

＆＃13;

var bodyParser = require('body-parser');
var express = require('express');
var mongoose = require('mongoose');

var Schema = mongoose.Schema;
var ObjectId = Schema.ObjectId;

var User = mongoose.model('User', new Schema({
	id: ObjectId,
	firstName: String,
	lastName: String,
	email: { type: String, unique: true },
	password: String,
}));

var app = express();
app.set('view engine', 'jade');
app.locals.pretty = true;

// conenct to mongo
mongoose.connect('mongodb://localhost/auth');

// middleware
app.use(bodyParser.urlencoded({ extended: true }));

app.get('/', function(req, re6s) {
	res.render('index.jade');
});

app.get('/register', function(req, res) {
	res.render('register.jade');
});

app.post('/register', function(req, res) {
	var user = new User({
		firstName: req.body.firstName,
		lastName: req.body.lastName,
		email: req.body.email,
		password: req.body.password
	});
	user.save(function(err) {
		if (err) {
			var err = "Something bad happened! Try again!";
			if (err.code === 11000) {
				error = "That email is already taken. Try another.";
			}
			res.render("register.jade", { error: error });
		} else {
			res.redirect("/dashboard");
		}
	});
});

app.get('/login', function(req, res) {
	res.render('login.jade');
});

app.get('/dashboard', function(req, res) {
	res.render('dashboard.jade');
});

app.get('/logout', function(req, res) {
	res.redirect('/');
});

app.listen(3000);

＆＃13;

完整错误消息：

>node app.js
module.js:339
    throw err;
    ^

Error: Cannot find module 'express'
    at Function.Module._resolveFilename (module.js:337:15)
    at Function.Module._load (module.js:287:25)
    at Module.require (module.js:366:17)
    at require (module.js:385:17)
    at Object.<anonymous> (C:\Users\mechart\Desktop\auth\app.js:2:15)
    at Module._compile (module.js:435:26)
    at Object.Module._extensions..js (module.js:442:10)
    at Module.load (module.js:356:32)
    at Function.Module._load (module.js:311:12)
    at Function.Module.runMain (module.js:467:10)

Answer 1

Can't find module 'Express'表示快速模块未正确安装在可从项目访问的路径中。您需要使用NPM安装该模块。与您在此项目中使用的任何其他模块相同。它应该像更改到应用程序目录一样简单，然后在控制台中发出以下命令：

npm install express

您还有另一个应该修复的错误。

重复的变量定义导致错误处理无法正常工作

在此代码中，您有一个名为err的参数，然后您还有var err。这将使你的参数被本地声明的var覆盖，你的错误处理将无效：

改变这个：

user.save(function(err) {
    if (err) {
        var err = "Something bad happened! Try again!";
        if (err.code === 11000) {
            error = "That email is already taken. Try another.";
        }
        res.render("register.jade", { error: error });
    } else {
        res.redirect("/dashboard");
    }
});

到此：

user.save(function(err) {
    if (err) {
        // change this variable name to errMsg in each place you use it
        var errMsg = "Something bad happened! Try again!";
        if (err.code === 11000) {
            errMsg = "That email is already taken. Try another.";
        }
        res.render("register.jade", { error: errMsg });
    } else {
        res.redirect("/dashboard");
    }
});

为什么我的代码会抛出错误？

1 个答案: