不处理的promise拒绝警告-不处理的promise拒绝警告

Question

我得到这个错误-

（节点：18420）未处理的PromisejectionWarning:TypeError:无法读取未定义的属性“name”

at C:\Users\ohrid\Desktop\backend2\routes\categories.js:27:24
at Layer.handle [as handle_request] (C:\Users\ohrid\Desktop\backend2\node_modules\express\lib\router\layer.js:95:5)
at next (C:\Users\ohrid\Desktop\backend2\node_modules\express\lib\router\route.js:137:13)
at Route.dispatch (C:\Users\ohrid\Desktop\backend2\node_modules\express\lib\router\route.js:112:3)
at Layer.handle [as handle_request] (C:\Users\ohrid\Desktop\backend2\node_modules\express\lib\router\layer.js:95:5)
at C:\Users\ohrid\Desktop\backend2\node_modules\express\lib\router\index.js:281:22     
at Function.process_params (C:\Users\ohrid\Desktop\backend2\node_modules\express\lib\router\index.js:335:12)
at next (C:\Users\ohrid\Desktop\backend2\node_modules\express\lib\router\index.js:275:10)
at Function.handle (C:\Users\ohrid\Desktop\backend2\node_modules\express\lib\router\index.js:174:3)
at router (C:\Users\ohrid\Desktop\backend2\node_modules\express\lib\router\index.js:47:12)
at Layer.handle [as handle_request] (C:\Users\ohrid\Desktop\backend2\node_modules\express\lib\router\layer.js:95:5)
at trim_prefix (C:\Users\ohrid\Desktop\backend2\node_modules\express\lib\router\index.js:317:13)
at C:\Users\ohrid\Desktop\backend2\node_modules\express\lib\router\index.js:284:7       
at Function.process_params (C:\Users\ohrid\Desktop\backend2\node_modules\express\lib\router\index.js:335:12)
at next (C:\Users\ohrid\Desktop\backend2\node_modules\express\lib\router\index.js:275:10)
at logger (C:\Users\ohrid\Desktop\backend2\node_modules\morgan\index.js:144:5)

（节点：18420）未处理的PromisejectionWarning:未处理的promise拒绝。此错误源于在没有catch块的情况下抛出异步函数的内部，或者拒绝使用未处理的promise。catch（）。要在未处理的promise拒绝时终止节点进程，请使用CLI标志--unhandled rejections=strict（请参阅https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode)（拒绝id:1）

（节点：18420）[DEP0018]弃用警告：未处理的promise拒绝已弃用。将来，未处理的promise拒绝将终止节点。具有非零退出代码的js进程。

我的路线/categories.js：

const { Category } = require('../models/category')
const express = require('express')
const router = express.Router()
 
router.get(`/`, async (req, res) => {
    const categoryList = await Category.find()
 
    if (!categoryList) {
        res.status(500).json({ success: false })
    }
    res.status(200).send(categoryList)
})
 
router.get('/:id', async (req, res) => {
    const category = await Category.findById(req.params.id)
 
    if (!category) {
        res.status(500).json({
            message: 'The category with the given ID was not found.',
        })
    }
    res.status(200).send(category)
})
 
router.post('/', async (req, res) => {
    let category = new Category({
        name: req.body.name,
        icon: req.body.icon,
        color: req.body.color,
    })
    category = await category.save()
 
    if (!category)
        return res.status(400).send('the category cannot be created!')
 
    res.send(category)
})
 
router.put('/:id', async (req, res) => {
    const category = await Category.findByIdAndUpdate(
        req.params.id,
        {
            name: req.body.name,
            icon: req.body.icon || category.icon,
            color: req.body.color,
        },
        { new: true }
    )
 
    if (!category)
        return res.status(400).send('the category cannot be created!')
 
    res.send(category)
})
 
router.delete('/:id', (req, res) => {
    Category.findByIdAndRemove(req.params.id)
        .then((category) => {
            if (category) {
                return res
                    .status(200)
                    .json({
                        success: true,
                        message: 'the category is deleted!',
                    })
            } else {
                return res
                    .status(404)
                    .json({ success: false, message: 'category not found!' })
            }
        })
        .catch((err) => {
            return res.status(500).json({ success: false, error: err })
        })
})
 
module.exports = router

我的应用程序。js

const express = require('express')
const app = express()
const morgan = require('morgan')
const mongoose = require('mongoose')
const cors = require('cors')
const dotenv = require('dotenv')
require('dotenv/config')
 
app.use(cors())
app.options('*', cors())
 
//middleware
app.use(morgan('tiny'))
 
//Routes
const categoriesRoutes = require('./routes/categories')
const productsRoutes = require('./routes/products')
const usersRoutes = require('./routes/users')
const ordersRoutes = require('./routes/orders')
 
const api = process.env.API_URL
 
app.use(`${api}/categories`, categoriesRoutes)
app.use(`${api}/products`, productsRoutes)
app.use(`${api}/users`, usersRoutes)
app.use(`${api}/orders`, ordersRoutes)
 
mongoose
    .connect(
        'mongodb+srv://dani:[e-mail]/e-shop?retryWrites=true&w=majority',
        {
            useNewUrlParser: true,
            useUnifiedTopology: true,
            dbName: 'e-shop',
        }
    )
    .then(() => {
        console.log('Database connection is ready')
    })
    .catch((err) => {
        console.log(err)
    })
 
app.listen(4000, () => {
    console.log('server is running on http://localhost:4000')
})

我应该换什么？

Answer 1

您的应用程序中没有任何错误处理层。

如果您使用Express v5及以上版本，返回Promise的路由处理程序和中间件将捕获错误，并自动调用Next（value）。

否则，从异步函数中，您必须将它们传递给Next（）函数，Express将在其中捕获并处理它们。

这样，您就不会得到UnHandledPromiseRejtionWarning。