node.js - express + Mongoose : async/await returning undefined

Question

我试图将路由代码与数据库代码分开，但当路由调用 Controller 方法时，我遇到了错误。

我有productRoutes.js:

router.route('/')
    .get(async (req, res, next) => {
        try {
            let criteria = {};
            for (const el in req.query) {
                criteria[el] = req.query[el];
            }
            console.log('Getting all products', criteria);

            const result = await controller.getAll(criteria);
            console.log('router result:', result);
            const status = (result.ok ? (result.count > 0 ? 200 : 404 ) : 400);
            return res.status(status).send(result);
        } catch (err) {
            return next(err);
        }
    });

productController.js:

exports.getAll = (criteria) => {
    model.find(criteria, '-__v').exec((err, records) => {
        const ok = (err ? false : true);

        let result = {}
        result.ok = ok;
        if (ok) {
            result.data = records;
            result.count = records.length;
        } else {
            result.count = 0;
            result.err = err;
        }

        console.log('controller result count:', result.count);

        return result;
    });
}

执行时会产生以下结果:

Getting all products {}
router result: undefined
TypeError: Cannot read property 'ok' of undefined
    at router.route.post.get (C:\dev\projects\mercante\server\routes\productRoutes.js:58:36)
    at <anonymous>
    at process._tickCallback (internal/process/next_tick.js:188:7)
controller result count: 4

执行不会等待 controller.getAll(criteria)。

我尝试过一些寻找类似问题的代码，例如 try/catch 异步调用，但没有成功或者我错过了一些细节。

提前致谢。

Answer 1

原因:您的 Controller 的 getAll 方法没有返回任何值。

你应该这样做:

exports.getAll = async (criteria) => {
    // Return value!
    return await model.find(criteria, '-__v');
}