MongoDB withTransaction

with-transaction.ts

// The docs for mongodb native driver sessions are pretty bare. The best example I can find is
// https://www.mongodb.com/blog/post/quick-start-nodejs--mongodb--how-to-implement-transactions
// but the code is generally not pretty; I think the following is likely the most suitable API:
// const doc = withTransaction(async session => {
//   const doc = await users.updateOne({ _id: id }, { $set: { email } }, { returnOriginal: false, session });
//   await orders.updateMany({ email }, { $set: { userId: id } }, { session });
//   return doc;
// });
const withTransaction = async <T>(
  fn: (session: ClientSession) => Promise<T>
) => {
  const session = mongoClient.startSession();
  try {
    let result: T;
    await session.withTransaction(async () => {
      // https://jira.mongodb.org/browse/NODE-2014
      result = await fn(session);
    });
    // @ts-ignore
    return result;
  } finally {
    await session.endSession();
  }
};