如何將我的貓鼬 PROMISE 鏈交易遷移到 ASYNC / AWAIT 流？

Question

我創建了一個將數據庫響應集成到承諾流中的 API，但我認為代碼的解釋很復雜，我相信 async/await 方法可以提高理解和代碼本身。

該 API 使用 mongoose 5.6.1 和 express 4.17.1 在 NodeJS 中構建。

你能幫我改進嗎？

以下是我想要改進的 API：

/** New employee */
router.post('/', (req, res) => {
    let { idCompany, name, departament } = req.body;
    let _id = mongoose.Types.ObjectId(); // Generating new MongoDB _ID
    let employeeCreated;

    const promise1 = new Promise((resolve, reject) => {
        // Querying by document '$oid'
        Companies.findOne({ _id: idCompany }, (err, company) => {
            // Error returned
            if (err) reject({ error: "Invalid request, something went wrong!" });
            // Invalid data received
            if (!company) reject({ error: "Unauthorized action!" });
            // Everything OK
            resolve(company);

        });
    })
    .then(company => {
        if(company) {
            const promise2 = new Promise((resolve, reject) => {
                Employees.create({ _id, idCompany, name, departament }, (err, employee) => {
                    // Error returned
                    if (err) reject({ error: "Invalid request, something went wrong!", err });
                    // Everything OK
                    employeeCreated = employee;
                    resolve(company);
                });
            })
            return promise2;
        }else reject({ error: "Company not found!" });
    })
    .then(company => {
        let { name: companyName, address, email, tel, employees } = company;
        employees.push(_id);

        const promise3 = new Promise((resolve, reject) => {
            Companies.findByIdAndUpdate(
                { _id: idCompany },
                { $set: { _id: idCompany, name: companyName, address, email, tel, employees } }, // spotlight
                { new: true },
                (err, company) => {
                    // Something wrong happens
                    if (err) reject({ success: false, error: "Can't update company!" });
                    // Everything OK
                    resolve(company);
                }
            );
        });
        return promise3;
    });

    promise1
        .then(() => res.json({ success: true, employeeCreated }))
        .catch(err =>   res.status(400).json({ error: "Invalid request, something went wrong!", err }));
});

問候。

Answer 1

在 mongoose 中使用 promise 的一個關鍵是使用exec方法：

您的代碼可能看起來像這樣（未經測試）：

router.post('/', async (req, res) => {
    try {
        const { idCompany, name, departament } = req.body;
        const _id = mongoose.Types.ObjectId();
        const company = await Companies.findOne({ _id: idCompany }).exec();
        const employeeCreated = await Employees.create({ _id, idCompany, name, departament });
        const { name: companyName, address, email, tel, employees } = company;
        employees.push(_id);
        await Companies.findByIdAndUpdate(
                    { _id: idCompany },
                    { $set: { _id: idCompany, name: companyName, address, email, tel, employees } }, // spotlight
                    { new: true }).exec();
        res.json({ success: true, employeeCreated });
    } catch(err) {
        res.status(400).json({ error: "Invalid request, something went wrong!", err });
    }
});

如果您認為有必要，您可以在try塊中拋出一些特定的自定義錯誤。

Answer 2

您可以簡單地使您的承諾運行的功能異步，因此您可以等待承諾解決。

例如，在你的路線中使用這個：

router.post('/', async (req, res) => {

然后在執行異步操作時，使用這個：

const company = await Companies.findOne({ _id: idCompany }).exec();

另外，我建議你用 try 和 catch 語句來包裝它

希望能幫助到你！