Javascript DB回调后的快速应用程序使用

我正在Nodejs Express应用程序中使用以下代码：

app.js:

// ... all variables are initialized
var orm = null;
var app = express();

db.create(dbSchema, dbSeeds, dbOptions, function(err, ormObject) {
    if (err) throw err;
    orm = ormObject;
});

var coursesRoutes = require('./routes/dashboard/courses')(orm);
app.use('/dashboard/courses', coursesRoutes);

var express = require('express');
var router = express.Router();

module.exports = function(orm) {

    router.get('/listall', function(req, res, next) {
        orm.loadMany('sections', null, function(err, sections) {
            if (err) throw err;
            res.jsonp(sections);
        });
    });
    return router;
};

/routes/dashboard/courses.js:

// ... all variables are initialized
var orm = null;
var app = express();

db.create(dbSchema, dbSeeds, dbOptions, function(err, ormObject) {
    if (err) throw err;
    orm = ormObject;
});

var coursesRoutes = require('./routes/dashboard/courses')(orm);
app.use('/dashboard/courses', coursesRoutes);

var express = require('express');
var router = express.Router();

module.exports = function(orm) {

    router.get('/listall', function(req, res, next) {
        orm.loadMany('sections', null, function(err, sections) {
            if (err) throw err;
            res.jsonp(sections);
        });
    });
    return router;
};

这将返回以下错误：

TypeError:无法读取null的属性“loadMany”

我知道问题是

orm

变量在

db.create

回调中初始化之前被传递到文件，但我不知道如何解决这个问题

我试着说：

var coursesRoutes = require('./routes/dashboard/courses')(orm);
app.use('/dashboard/courses', coursesRoutes);

---

在回调内部，但返回404 not found

在建立数据库连接之前调用了您的courses函数

这应该能奏效

var orm = null;
var app = express();

db.create(dbSchema, dbSeeds, dbOptions, function(err, ormObject) {
    if (err) throw err;
    orm = ormObject;
    var coursesRoutes = require('./routes/dashboard/courses')(orm);
    app.use('/dashboard/courses', coursesRoutes);
});

---

这将返回404notfound