React/Redux-Offline point of sale application

As a proof of concept this application will function as a progressive offline first app.

How does it work?

• Service worker (production build only) will cache all assets on first load and prioritise the use of them on subsequent page loads
• Product details and stock levels from the API are stored using rt2zz/redux-persist and re-hydrated if they can't be collected
• redux-offline/redux-offline monitors the online/offline status of the app and will queue up any requests that fail to be processed once the app goes back online

Installation:

1. git clone https://github.com/chriscornford/pos-react.git
2. cd pos-react && yarn
3. Ensure to add correct domain depending on your setup to API_URL inside config.js
4. Run development build yarn start and navigate to given local URL

Running production build

1. Follow installation steps
2. yarn build
3. yarn add global serve
4. serve -s build

Potential issues to consider:

• Item stock levels aren't real time, could run into issues if a product goes out of stock (using sockets would help solve this).
• Product API won't be able to handle pulling down thousands of products at a time.
• On refresh cart overrides its contents with the default state, this would cause issues as stock still appears to have decreased (redux-persist is being greedy and persisting changes to stock levels).
• If the API comes back with an error due to an item being out of stock the app doesn't handle it.

As this is a rough prototype here are the ways I would improve it:

• Add spec tests
• Ensure all components and containers have correct prop types
• Use immutable.js and reselect to clean up nasty code
• Use sockets to get more accurate real time data!!
• Use Eslint to ensure consistent code

References:

• Introducing Redux Offline: Offline-First Architecture for Progressive Web Applications and React Native
• https://github.com/redux-offline/redux-offline
• https://github.com/reduxjs/redux/tree/master/examples/shopping-cart

This project was bootstrapped with Create React App, which provides a simple way to start React projects with no build configuration needed.