node.js - 在 Nodejs 中导出变量时出现未定义的错误

Question

这是我的 managedb.js

var Sequelize = require('sequelize-postgres').sequelize;
var postgres  = require('sequelize-postgres').postgres;

 var db = new Sequelize('test', 'postgres', 'postgres', {
  dialect: 'postgres'
});


var models = [
'user'
];

models.forEach(function(model) {
module.exports[model] = db.import(__dirname + '/' + model);
});



module.exports.db = db;

这是我的 user.js

var sequelize = require("sequelize");
var seq = require("./managedb");
var db = seq.db;

var Project = db.define('Project', {
  title: sequelize.STRING,
  description: sequelize.TEXT
});

我很困惑为什么会收到此错误：

var Project = db.define('Project', {
                 ^
TypeError: Cannot call method 'define' of undefined

为什么会出现这种情况？我是否导出变量错误？或者我是否必须向 managedb.js 添加一个 db.sync() 语句？