Mongoose/Mongo：更新不保存

Question

我对 mongo/mongoose 遇到的这个问题感到非常困惑。我实际上是在尝试获取产品数组，从数组中删除某个产品，然后使用省略所选产品的新数组更新购物图表。这是我正在处理的代码的 sn-p：

const remove = (req, res, next) => {
  console.log('here is the product id ' + req.body.cart.product)
  delete req.body._owner // disallow owner reassignment.
  Cart.find({_id: req.user.cartId})
  .then((products1) => {
    console.log("array of products: " + products1[0].product)
    const index = products1[0].product.indexOf(req.body.cart.product)
    console.log("index valeu: " + index)
    if (index > -1) {
      products1[0].product.splice(index, 1)
      return products1[0].product
    }
    return products1[0].product
  })
  .then((products2) => {
    console.log('Second Promise Input: ' + products2)
    Cart.update({_id: req.user.cartId}, {$set: {product: products2}})
  })
  .then(() => res.sendStatus(204))
  .catch(next)
  }

这是我服务器的输出：

Server listening on port 4741
here is the product id 5952b57ea52d092b8d34c6b0
array of products: 5952b57ea52d092b8d34c6b0,5952b57ea52d092b8d34c6b0,5952b57ea52d092b8d34c6b0,5952b57ea52d092b8d34c6b0,5952b57ea52d092b8d34c6b0
index valeu: 0
Second Promise Input: 5952b57ea52d092b8d34c6b0,5952b57ea52d092b8d34c6b0,5952b57ea52d092b8d34c6b0,5952b57ea52d092b8d34c6b0
PATCH /carts-decrease/595b037e128cfd37e0c864d7 204 38.773 ms 

根据我的 console.logs，我得到了我想要的数组，但它根本不会用新数组更新购物车。我已经盯着这段代码太久了，我很感激第二次关注这个。谢谢。

附：忽略产品ID都相同的事实，它只是一个测试变量

购物车架构：

'use strict'

const mongoose = require('mongoose')

const cartSchema = new mongoose.Schema({
  product: {
    type: Array,
    required: false
  },
  owner: {
    type: mongoose.Schema.Types.ObjectId,
    ref: 'User',
    required: false
  }
}, {
  timestamps: true,
  toJSON: {
    virtuals: true,
    transform: function (doc, ret, options) {
      const userId = (options.user && options.user._id) || false
      ret.editable = userId && userId.equals(doc._owner)
      return ret
    }
  }
})

const Cart = mongoose.model('Cart', cartSchema)

module.exports = Cart

产品架构：

'use strict'

const mongoose = require('mongoose')

const productSchema = new mongoose.Schema({
  name: {
    type: String,
    required: true
  },
  price: {
    type: Number,
    required: true
  },
  description: {
    type: String,
    required: true
  }
}, {
  toJSON: {
    virtuals: true
  }
})

const Product = mongoose.model('Product', productSchema)

module.exports = Product

显示请求：

const show = (req, res) => {
  const product = {}
  product.array = []
//  console.log(req.cart.product)
  const promises = []

  Promise.all(req.cart.product.map(function (id) {
    return Product.find({_id: ObjectId(id)})
  })).then(function (products) {
    console.log(products)
    req.cart.product = products
    return res.json({
      cart: req.cart.toJSON({virtuals: true, user: req.user})
    })
  }).catch(function (err) {
    console.log(err)
    return res.sendStatus(500)
  })
}

Answer 1

我建议你稍微修改一下你的cartSchema，并以embedded documents数组的形式存储产品：

const cartSchema = new mongoose.Schema({
    products: [{
        name: { type: String },
        price: { type: Number }
        ...
    }]
    ...
});

如果您这样做，您可以简单地使用 $pull 更新运算符从您的购物车中删除产品：

{ $pull: { <field1>: <value|condition>, <field2>: <value|condition>, ... } }

在您的情况下，查询应如下所示：

Cart.update(
    { _id: req.user.cartId },
    { $pull: { products: { '_id': req.body.cart.product } }}
);

由于嵌入的文档将有自己的 ObjectId，因此只有一个文档与查询匹配。