Example of bulk write transaction with Mongo 4.0 in Node.js

mongo-transaction-playground.ts

import { Backend } from '../../db/connection';
import { MongoClient, Db } from 'mongodb';
import { setupCliEnv } from './setup-cli-env';

export async function mongoTransactionTest() {
    setupCliEnv('development', false);

    const options = {
        useNewUrlParser: true,
        useUnifiedTopology: true,
    };
    const client = await MongoClient.connect(config.mongo.connectionString, options);
    const db = client.db('db-name');

    await db.collection('Account').deleteMany({});
    await db.collection('Account').insertMany([
        { name: 'A', balance: 5 },
        { name: 'B', balance: 5 },
    ]);

    const session = client.startSession();
    session.startTransaction();
    try {
        // await db
        //     .collection('Account')
        //     .findOneAndUpdate({ name: 'A' }, { $set: { balance: 6 } }, { session });
        // await db
        //     .collection('Account')
        //     .findOneAndUpdate({ name: 'B' }, { $set: { balance: 6 } }, { session });
        await db.collection('Account').bulkWrite(
            [
                {
                    updateOne: {
                        filter: { name: 'A' },
                        update: { $set: { balance: 6 } },
                    },
                },
                {
                    updateOne: {
                        filter: { name: 'B' },
                        update: { $set: { balance: 6 } },
                    },
                },
            ],
            { session }
        );
        await db
            .collection('Account')
            .findOneAndUpdate({ name: 'B' }, { balance: 7 }, { session });
        await session.commitTransaction();
    } catch (error) {
        console.log(`🐛 was unexpected: ${error.message}`);
    } finally {
        session.endSession();
    }

    console.log('done! 😍');
    await client.close();
    process.exit(0);
}

mongoTransactionTest();

Nice, but how do you pass the json data as a variable?

This gist is actually outdated, see here for up-to-date example https://www.mongodb.com/blog/post/quick-start-nodejs--mongodb--how-to-implement-transactions