First install all dependencies
yarn --dev
Run the code
yarn start
Tests
yarn test
yarn test:watch
Coverage
yarn coverage
Assumptions
- Price rules are applied in priority order (in the order they are specified)
- Each price rule creates a new version of the checkout cart. This way each application of a price rule on a cart is a pure function of the cart content and rules
- We assume price rules are applied in priority order (in the order they are specified to checkout), as it ensures cross-cutting or conflicting price rules are applied safely and in order. (The alternative is to ensure price rules don't conflict ever which may not be a simple task as they change over time and are hard to govern)
- Regarding Scenario 3, since the the VGA is bundled into the cart, I have made the assumption that a new item will be added to the cart in addition to the VGA adapter already scanned in. This can easily be changed to assume that a VGA adapter must always be scanned in every time a macbook exists in the cart or throw an error. Since my assumption auto bundles a VGA adapter, Scenario 3 would have a total sum of 1979.98 rather than 1949.98. If there are any other VGA adapters added in, they would be full price (except if accompanying macbooks are added in)