Skip to content
Shopping cart with MobX and React
JavaScript CSS HTML
Branch: master
Clone or download
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Type Name Latest commit message Commit time
Failed to load latest commit information.

Description of the assignment:

Build a shopping cart that has the following functionality using this dummy API

  1. Show a grid of items with each item has price, thumbnail & "add to cart" button.
  2. Clicking one item should show more info about the item (description, price, remaining stock & add to cart button).
  3. When you click the add to cart button the item should be added to the cart and the stock number should be updated in the detail view of the item.
  4. The cart should have a checkout button, when clicked show a successful message and clear the cart.
  5. Design is left for you, it's not a design task so nothing fancy, but of course responsive. Functionality is more important.

Please provide a README file describing your rational, tools & ideas you used and why. Use git (github, gitlab or bitbucket repo) if possible, but if you can't provide a git repo somewhere make sure you send a zip file with the .git folder included.

Run Project

$ git clone
$ cd lightspeed
$ npm i
$ npm start

You need to have an .env in the root since I have used a custom-react-scripts package to support decorators and scss files with ease. The env files enable decorators (mobx) and scss/sass support. It should be included in the repo, but:



If using VSCode

You will have some experimental decorators warnings. Only warnings, it still compiles with no problem, but I know it can be annoying. Just create a tsconfig.json file in the root of the directory with this content:

    "compilerOptions": {
        "experimentalDecorators": true,
        "allowJs": true

Packages used

Package Url


I used mobx and its decorators to build this small shopping cart with basic functionality. I decided to use mobx since I have used it in the past, and for a fast assignment, it was my preferred choice. In my personal opinion, it's also a bit more readable.

Actions like adding products to the cart or calculating the total amount of the cart that are being occurred in this app, are located in src/stores/CartStore.js A problem I encountered, was that the json data from {product.price}, had a ',' when it was larger than $999. Decided to replace the comma with an empty string, with a parseFloat included in the product price.

Fetching API using axios is done in src/stores/ProductStore.js

In the components folder, we have a common folder which has a re-usable Modal.js and Success.js implemented in other components.

In the styles folder, we have basic .scss files with variables, media queries (responsiveness, a basic one) and other styling values.

In Home.js I render:

  • Cart.js => Renders the products added to your cart, and the total sum of it. Also, the ability to remove products.
  • ProductList.js => Renders the fetched data from the API. And yes, I used tables.
  • ItemsCount.js => Renders the quantity of items in the shopping cart.


  • CartStore.js => The sum of the total amount of products in the cart is done here. Also actions such as pushing products to the cart, emptying and removing products.
  • ProductStore.js => Using axios I fetch the API, so I can inject it (thanks to mobx's decorators) in Components such as ProductList

Rest of components:

  • Cart.js => Renders the content of the shopping cart which includes: Added products, Total Amount to be paid, and a checkout button which clears the shopping cart's content.
  • CartItem.js => Single products added to the shopping cart that are also removable. This is imported in cart.js.
  • MoreInfo.js => Renders the content of the modal when the users clicks on the "More Info" button on the main overview of the products (grid).
  • ProductList.js => Renders the grid of products.
  • ProductSingle.js => Rendering individual products where fetching data is being done by ProductStore.js.


Nothing much to add here. Used tables with light colours, and Roboto font just to make it look a bit more smooth.


The media queries variables (located in components/styles/_vars.scss) are being applied to the table and main wrapper only. Which still makes it responsive, but it can be worked on a lot.

Encountered Problems

  • As mentioned before, rendering the price and calculating the total wasn't working as expected. Until I found the solution to replace the ',' to an empty string.
  • Decorators were not being supported. I used Custom React Scripts ( with the custom .env file mentioned above.
  • Didn't have time to render the modal component Success.js on the OnClick function located on the Checkout Button in the shopping cart. But I know how to do it. I just added an alert, and when accepted, it clears the shopping cart.
  • I'm more comfortable using Styled Components (or Emotion), but a basic design using SASS was faster.
  • Folders should be more organized:
├── components
│   ├── App.js
│   ├── Cart.js
│   ├── CartItem.js
│   ├── Checkout.js
│   ├── Home.js
│   ├── ItemsCount.js
│   ├── MoreInfo.js
│   ├── ProductList.js
│   ├── ProductSingle.js
│   ├── common
│   │   ├── Modal.js
│   │   └── Success.js
│   └── styles
│       ├── _main.scss
│       ├── _vars.scss
│       └── background.svg
├── index.js
├── serviceWorker.js
└── stores
    ├── CartStore.js
    ├── ProductStore.js
    └── index.js
You can’t perform that action at this time.