Added inventory management

[BiswajitSahoo-tech]

Fixes [ #55 ]

Hi @roopeshsn,
I have added inventory management, below is a brief of my solution:

1. First created a updateStockCount function on backend/controller/productController/
   few notes on the updateStockCount function and how it handles the edge cases

   • var product = await Product.findById(id) - find the product by id passed as argument

   •  if(product.countInStock < qty){
            throw new Error(" A MESSAGE")
      }  
     

     The above code throws an Error if the Quantity demanded is more than in the stock amount of any product present on
     OrderItem
   • Finally, if everything goes well, then the below code will be executed and stock will be updated for each product
     corresponding to the given order.

     product.countInStock -= qty
     const updatedProduct = await product.save()
     

2. Add the following code in updateOrderToPaid function under backend/controller/orderController/

   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
     })
   }
   
   

   catch(err) will catch the error thrown by updateStockCount and immediately send a response to the client having
   an appropriate message of what actually happens also ends the request-response cycle such that in the case of a catch
   there will be no update on these fields.
   isPaid and paidAt - these fields are updated only when all the promises at updatePromises will be resolved successfully.

   order.isPaid = true
   order.paidAt = Date.now()
   

   The above code will execute only when all the promises at updatePromises will be resolved successfully.

3. I have tested the feature using Postman and it is working as expected.

4. No other breaking changes are made to the system

Thank You ❤️

[roopeshsn]

Hi, @BiswajitSahoo-tech Could you also check with the frontend and add an appropriate video or a screenshot?

[BiswajitSahoo-tech]

Ok @roopeshsn, Got it
will get back to you with screenshots
Thanks

[BiswajitSahoo-tech]

Hi @roopeshsn,
Below are the screenshots following the flow

1. User goes to a product page and adds it to the cart (Note: status is In Stock)
   

2. User goes to cart and clicks Proceed to checkout
   

3. After following all the intermediate steps, the User places the order
   

4. Now we make PUT request to api/orders/63417f09c2fadfe36a1f7699/pay, since we have to pay for the order in order to have updated the stock amount
   

5. After making the payment, see the status of the paid order page
   

6. Now also check the product page: ( Note: Status is now Out of stock)
   

Actually initially there is 5 kg carrot in stock and user ordered 5 kg carrots, therefore after payment we have carrot out of stock

[BiswajitSahoo-tech]

@roopeshsn, Please have a look.

[roopeshsn]

Hi @BiswajitSahoo-tech Could you remove that .env.sample file and all its imports? We have .env in the root. Also, the code is not formatted. There is a prettier command to format the recursively check the package.json file.

[BiswajitSahoo-tech]

Hi @roopeshsn,
I have formatted the code and removed the .env.sample file.
Please review it.

[roopeshsn]

You haven't added any packages in the package.json file right then why you have committed the file.

[BiswajitSahoo-tech]

@roopeshsn I removed it, check it now please

[roopeshsn]

Could you explain why this line is added?

[BiswajitSahoo-tech]

return updateProduct this line?
This is added such that the updated product will be in the resolved result of all promises that we awaiting in orderController.
But there is no requirement for this result, we can omit this.

[roopeshsn]

Good work @BiswajitSahoo-tech Let me know if you're interested to become a collaborator for this project.

[BiswajitSahoo-tech]

Thanks, @roopeshsn, for giving me this opportunity.
Just a doubt, what are the works of a project collaborator?

[roopeshsn]

The work of a maintainer or owner of a project. Collaborator will raise issues for a feature or a bug, review and merge PRs. In short, Collaborator will work for the improvement of the project.

[BiswajitSahoo-tech]

Sorry, @roopeshsn, we have a term exam scheduled next week so, I don't think I can contribute much as a collaborator. Thank you very much for the offer.