ecommerce-escalation v1

service.js

import _ from 'lodash';

export class InsufficientStock extends Error {
  constructor(message) {
    super(message);
    this.name = 'InsufficientStock';
  }
}

export default (repository) => {
  return {
    async checkout(lineItems, shippingAddress, paymentDetails) {
      for (const {productSku, quantity} of lineItems) {
        const {stock: remainingStock} = await repository.findInventoryByProductSku(productSku);
        if (remainingStock < quantity) {
          throw new InsufficientStock({
            productSku,
            remainingStock,
            requestedStock: quantity
          });
        }
        await repository.updateInventoryStockByProductSku(productSku, remainingStock - quantity);
      }

      const orderID = await repository.createOrder({
        lineItems,
        shippingAddress,
        paymentDetails
      });
      return orderID;
    }
  };
};