我正在构建一个库存管理应用程序，并且我想创建一个类似于购物车/产品系统的功能。我处于将产品添加到购物车的阶段，似乎无法找出有效的代码。
const mongoose = require("mongoose");
const CartSchema = new mongoose.Schema(
{
active: Bolean,
modifiedOn: Date,
product: [
{
qunantity: String,
name: String,
price: number
}
]
},
{ timestamps: true }
);
module.exports = mongoose.model("Cart", CartSchema);
购物车控制器：
exports.postCart = asyncHandler(async (req, res, next) => {
let cart = JSON.parse(req.body.cart);
if (!cart) return res.json(products)
for (var i = 0; i < products.length; i++) {
id = products[i].id.toString();
if (cart.hasOwnProperty(id)) {
products[i].qty = cart[id]
products.push(products[i]);
}
}
return res.json(products);
})
正在尝试建立类似upsert的功能，以便为提供的userId创建文档，如果尚不存在。事实是我已经尝试过但无法解决，任何有想法的人都会感激
答案 0 :(得分：1)
我认为购物车中的userId字段在购物车系统中是必须的。
所以我会这样设计我的模式：
const mongoose = require("mongoose");
const CartSchema = new mongoose.Schema(
{
userId: {
type: mongoose.Schema.Types.ObjectId,
ref: "User"
},
products: [
{
productId: Number,
quantity: Number,
name: String,
price: Number
}
],
active: {
type: Boolean,
default: true
},
modifiedOn: {
type: Date,
default: Date.now()
}
},
{ timestamps: true }
);
module.exports = mongoose.model("Cart", CartSchema);
请注意：
Number product字段重命名为products，因为它是一个数组。使用此架构，我将创建一条类似这样的路线以将商品添加到购物车：
router.post("/cart", async (req, res) => {
const { productId, quantity, name, price } = req.body;
const userId = "5de7ffa74fff640a0491bc4f"; //TODO: the logged in user id
try {
let cart = await Cart.findOne({ userId });
if (cart) {
//cart exists for user
let itemIndex = cart.products.findIndex(p => p.productId == productId);
if (itemIndex > -1) {
//product exists in the cart, update the quantity
let productItem = cart.products[itemIndex];
productItem.quantity = quantity;
cart.products[itemIndex] = productItem;
} else {
//product does not exists in cart, add new item
cart.products.push({ productId, quantity, name, price });
}
cart = await cart.save();
return res.status(201).send(cart);
} else {
//no cart for user, create new cart
const newCart = await Cart.create({
userId,
products: [{ productId, quantity, name, price }]
});
return res.status(201).send(newCart);
}
} catch (err) {
console.log(err);
res.status(500).send("Something went wrong");
}
});
我假设您已经具有登录用户的ID，我设置了一个硬编码的userId。
一些测试：
我们第一次为用户添加产品到购物车
{
"productId": 1,
"quantity": 1,
"name": "product 1",
"price": 11
}
响应如下：
{
"active": true,
"modifiedOn": "2019-12-04T19:02:12.673Z",
"_id": "5de802bbc68b882d4803473f",
"userId": "5de7ffa74fff640a0491bc4f",
"products": [
{
"_id": "5de802bbc68b882d48034740",
"productId": 1,
"quantity": 1,
"name": "product 1",
"price": 11
}
],
"createdAt": "2019-12-04T19:02:19.567Z",
"updatedAt": "2019-12-04T19:02:19.567Z",
"__v": 0
}
然后我们添加另一种产品：
{
"productId": 2,
"quantity": 2,
"name": "product 2",
"price": 22
}
响应如下：
{
"active": true,
"modifiedOn": "2019-12-04T19:02:12.673Z",
"_id": "5de802bbc68b882d4803473f",
"userId": "5de7ffa74fff640a0491bc4f",
"products": [
{
"_id": "5de802bbc68b882d48034740",
"productId": 1,
"quantity": 1,
"name": "product 1",
"price": 11
},
{
"_id": "5de802e3c68b882d48034741",
"productId": 2,
"quantity": 2,
"name": "product 2",
"price": 22
}
],
"createdAt": "2019-12-04T19:02:19.567Z",
"updatedAt": "2019-12-04T19:02:59.703Z",
"__v": 1
}
现在让我们尝试将productId = 2的数量更改为1。
{
"productId": 2,
"quantity": 1,
"name": "product 2",
"price": 22
}
响应如下：
{
"active": true,
"modifiedOn": "2019-12-04T19:02:12.673Z",
"_id": "5de802bbc68b882d4803473f",
"userId": "5de7ffa74fff640a0491bc4f",
"products": [
{
"_id": "5de802bbc68b882d48034740",
"productId": 1,
"quantity": 1,
"name": "product 1",
"price": 11
},
{
"_id": "5de802e3c68b882d48034741",
"productId": 2,
"quantity": 1,
"name": "product 2",
"price": 22
}
],
"createdAt": "2019-12-04T19:02:19.567Z",
"updatedAt": "2019-12-04T19:03:42.506Z",
"__v": 1
}
如您在响应中看到的，productId = 2的数量更改为1。
答案 1 :(得分：1)
您的购物车模型应如下所示：
const mongoose = require('mongoose');
const Schema = mongoose.Schema;
let ItemSchema = new Schema({
productId: {
type: mongoose.Schema.Types.ObjectId,
ref: "Product",
},
quantity: {
type: Number,
required: true,
min: [1, 'Quantity can not be less then 1.']
},
price: {
type: Number,
required: true
},
total: {
type: Number,
required: true,
}
}, {
timestamps: true
})
module.exports = mongoose.model('item', ItemSchema);
const CartSchema = new Schema({
userId: {
type: mongoose.Schema.Types.ObjectId,
ref: "User",
},
items: [ItemSchema],
subTotal: {
default: 0,
type: Number
}
}, {
timestamps: true
})
module.exports = mongoose.model('cart', CartSchema);
之后，您可以定义添加方法：
exports.addItemToCart = async (req, res) => {
const {
userId,
productId
} = req.body;
const quantity = Number.parseInt(req.body.quantity);
try {
// -------Get users Cart ------
let cart = await Cart.findOne({
userId: userId
})
//-----Get Selected Product Details ----
const productDetails = await Product.findById(productId);
//-- Check if cart Exists and Check the quantity if items -------
if (!cart && quantity item.productId == productId);
//------this removes an item from the the cart if the quantity is set to zero,We can use this method to remove an item from the list --------
if (indexFound !== -1 && quantity item.total).reduce((acc, next) => acc + next);
}
//----------check if product exist,just add the previous quantity with the new quantity and update the total price-------
else if (indexFound !== -1) {
cart.items[indexFound].quantity = cart.items[indexFound].quantity + quantity;
cart.items[indexFound].total = cart.items[indexFound].quantity * productDetails.price;
cart.items[indexFound].price = productDetails.price
cart.subTotal = cart.items.map(item => item.total).reduce((acc, next) => acc + next);
}
//----Check if Quantity is Greater than 0 then add item to items Array ----
else if (quantity > 0) {
cart.items.push({
productId: productId,
quantity: quantity,
price: productDetails.price,
total: parseInt(productDetails.price * quantity)
})
cart.subTotal = cart.items.map(item => item.total).reduce((acc, next) => acc + next);
}
//----if quantity of price is 0 throw the error -------
else {
return res.status(400).json({
type: "Invalid",
msg: "Invalid request"
})
}
let data = await cart.save();
res.status(200).json({
type: "success",
mgs: "Process Successful",
data: data
})
}
//------------ if there is no user with a cart...it creates a new cart and then adds the item to the cart that has been created------------
else {
const cartData = {
userId: userId,
items: [{
productId: productId,
quantity: quantity,
total: parseInt(productDetails.price * quantity),
price: productDetails.price
}],
subTotal: parseInt(productDetails.price * quantity)
}
cart = new Cart(cartData);
let data = await cart.save();
res.json(data);
}
} catch (err) {
console.log(err)
res.status(400).json({
type: "Invalid",
msg: "Something Went Wrong",
err: err
})
}
}