出现错误：slugify：需要字符串参数

Question

我尝试为电子商务项目创建类别，然后它抛出错误

这些是源代码

位置：电子商务后端\index.js

    const express = require('express')
    const env = require('dotenv')
    const app = express()
    const mongoose = require('mongoose')


    //routes
    const authRoutes = require('./routes/auth')
    const adminRoutes = require('./routes/admin/auth')
    const categoryRoutes = require('./routes/category')
    const productRoutes = require('./routes/product')
    const cartRoutes = require('./routes/cart')
    //environment variable or you can say constants
    env.config()

    //mongodb connection
    mongoose.connect(
        `mongodb+srv://${process.env.MONGO_DB_USERS}:${process.env.MONGO_DB_PASSWORD}@cluster0.nglbc.mongodb.net/${process.env.MONGO_DB_DATABASE}?retryWrites=true&w=majority`, 
        {
            useNewUrlParser: true, 
            useUnifiedTopology: true,
            useCreateIndex: true
        }
    ).then(() => {
        console.log('Database connected')
    });

    app.use(express.json())
    app.use('/api', authRoutes)
    app.use('/api', adminRoutes)
    app.use('/api', categoryRoutes)
    app.use('/api', cartRoutes)
    app.use('/api', productRoutes)

    app.listen(process.env.PORT, () => {
        console.log(`Server is running on port ${process.env.PORT}`)
    })

位置：电商后台 欧特