ecommerce-escalation v2 repo

repository.js

export default (mongoClient, db) => {
  return {
    async checkoutTransaction(closure) {
      const session = mongoClient.startSession({
        causalConsistency: true
      });
      try {
        const sessionRepository = {
          async findInventoryByProuctSkus(productSkus) {
            return db.collection('inventory').find({
              productSku: {
                $in: productSkus
              }
            }, {
              session
            })
              .toArray();
          },

          async updateInventoryStock(updates) {
            return db.collection('inventory').bulkWrite(updates.map(({productSku, stock}) => {
              return {
                updateOne: {
                  filter: {
                    productSku
                  },
                  update: {
                    $set: stock
                  }
                }
              }
            }), {
              session
            });
          },

          async createOrder(order) {
            const {insertedId} = await db.collection('order').insertOne(order, {
              session
            });
            return insertedId;
          }
        };

        return session.withTransaction(closure(sessionRepository));
      } finally {
        await session.endSession();
      }
    }
  };
};