Added inventory management

backend/.env.sample

@@ -0,0 +1,4 @@
+MONGODB_URI=
+PORT=
+NODE_ENV=
+JWT_SECRET=

backend/config/db.js

@@ -2,7 +2,7 @@ const mongoose = require('mongoose')
 
 const connectDB = async () => {
   try {
-    const conn = await mongoose.connect(process.env.MONGODB_URI, {
+      const conn = await mongoose.connect(process.env.MONGODB_URI, {
       useNewUrlParser: true,
       useUnifiedTopology: true,
     })

backend/controllers/orderControllers.js

@@ -1,6 +1,7 @@
 const asyncHandler = require('express-async-handler')
 const Order = require('../models/orderModel')
 const Product = require('../models/productModel')
+const productController = require('./../controllers/productController')
 
 // @desc    Create new order
 // @route   POST /api/orders
@@ -17,7 +18,8 @@ const addOrderItems = asyncHandler(async (req, res) => {
   // Product price validation
   orderItems.forEach(async (item) => {
     let lookupItem = await Product.findById(item.product)
-    if (item.price !== lookupItem.price) {
+    if (parseFloat( item.price) !== lookupItem.price) {
+
       res.status(400)
       throw new Error(
         'There is a discrepancy between the prices of the items, and whats in the Database, please try again!',
@@ -91,6 +93,21 @@ const updateOrderToPaid = asyncHandler(async (req, res) => {
   const order = await Order.findById(req.params.id)
 
   if (order) {
+    //below .map() function return an array of promises
+    const updatePromises = order.orderItems.map(async (item)=> {
+      await productController.updateStockCount( req, res, item.product,parseInt( item.qty))
+    })
+    //below function to resolve the array of promises
+    try{
+      await Promise.all( updatePromises)
+    }catch( error){
+      return res.status(404).json({
+        status:'fail',
+        message: error.message
+      })
+    }
+
+
     order.isPaid = true
     order.paidAt = Date.now()
     const updatedOrder = await order.save()

backend/controllers/productController.js

@@ -117,10 +117,28 @@ const updateProduct = asyncHandler(async (req, res) => {
   }
 })
 
+const updateStockCount =asyncHandler( async (req, res, id, qty)=>{
+  try{
+    var product = await Product.findById(id)
+  }catch(err){
+    throw new Error(err.message)
+  }
+
+  if(product.countInStock < qty){
+    throw new Error("We are really sorry. We have not "+qty+" amount of "+
+          product.name+" currently on stock. Either you wait for stock to fullfilled or you can decrease your ordered quantity of "+product.name)
+  }
+  product.countInStock -= qty
+  const updatedProduct = await product.save()
+  return updateProduct
+
+})
+
 module.exports = {
   getProducts,
   getProductById,
   deleteProduct,
   createProduct,
   updateProduct,
+  updateStockCount
 }

package.json

@@ -40,6 +40,7 @@
     "mongoose": "^6.4.6",
     "multer": "^1.4.3",
     "nodemailer": "^6.6.5"
+
   },
   "devDependencies": {
     "chai": "^4.3.6",