transactions-mongoose

Transactions for mongoose

Transactions allow you to perform multiple group operations in isolation and undo all operations if one of them fails.

This module allows you to combine different transactions and operations into a group and execute them together. Pre-checks the schema for errors, duplication of unique indexes/fields

Install module

npm i transactions-mongoose

Usage

const Transaction = require("transactions-mongoose");
const transaction = new Transaction();
// or with debug log
const transaction = new Transaction().setSendbox(true);

An exemplary use case

Create / Insert new document

const Transaction = require("transactions-mongoose");
const transaction = new Transaction().setSendbox(true);

const transactionData1 = transaction.add(Person, {
    firstname: 'Sancho',
    lastname: 'Panse',
    age: 22,
    sex: 'male',
    status: 'free'
});
const transactionData2 = transaction.add(Person, {
    firstname: 'Janna',
    lastname: 'Dark',
    age: 21,
    sex: 'famale',
    status: 'free'
});
transaction.add(Person, {
    firstname: 'Hulio',
    lastname: 'Iglessias',
    age: 35,
    sex: 'male',
    status: 'free'
});
await transaction.commit();

console.log('transaction 1', transactionData1.result) // the result of the save() operation
console.log('transaction 2 document', transactionData2.document)

Update an existing one

const Transaction = require("transactions-mongoose");
const transaction = new Transaction().setSendbox(true);

// variant #1 - use standard setters
let personSancho = await Person.findById('...Sancho id');
personSancho.age += 1;
personSancho.status = 'married';
personSancho.friend_id = '...Hulio Iglessias id';
transaction.add(Person, personSancho);

// variant #2 - by document and update object
let personJanna = await Person.findById('...Janna id');
transaction.add(Person, personJanna).update({
    age: ++personJanna.age,
    status: 'married',
    friend_id: personSancho._id,
    bodyFriend_id: '...Hulio Iglessias id',
});

// variant #3 - by ObjectId
transaction.add(Person, {_id: '...Sancho id'}).update({
    friend_id: personJanna._id
});

await transaction.commit();

Executing an isolated block that may fail is not related to Mongo but affects whether the data is saved or not.

const fetch = require("node-fetch");
const Transaction = require("transactions-mongoose");
const transaction = new Transaction().setSendbox(true);

const getAvatar = async (id) => {
    const response = await fetch('https://i.pravatar.cc/300?u=' + id);
    const blob = await response.blob();
    return new Promise((onSuccess, onError) => {
        const reader = new FileReader() ;
        reader.onload = function(){ onSuccess(this.result) } ;
        reader.readAsDataURL(blob) ;
    });
};

const transactionData = transaction.execute(async () => {
    let personSancho = await Person.findById('...Sancho id');
    transaction.add(Person, personSancho).update({
        updatedAt: Date.now(),
        __v: ++personSancho.__v
    });
    // there may be a timeout error or a reader processing error
    personSancho.avatar = await getAvatar(personSancho._id)

    transaction.execute(async () => {
        let personHulio = await Person.findById('...Hulio id');
        personHulio.avatar = await getAvatar(personHulio._id);
        transaction.add(Person, personHulio)
    });

    let personJanna = await Person.findById('...Janna id');
    personJanna.avatar = await getAvatar(personJanna._id);
    const td = transaction.add(Person, personJanna)
    
    // The result can be whatever you want
    // we will return the Janna document update result
    // https://mongoosejs.com/docs/api/query.html#Query.prototype.updateOne()
    return td.result 
});

// and also execute it :)
personJanna.updatedAt = Date.now()
transaction.add(Person, personJanna)

await transaction.commit();
console.log('transaction result', transactionData.result);

With session executor

const Transaction = require("transactions-mongoose");
const transaction = new Transaction().setSendbox(true);

transaction.session(async (session) => {
    let personJanna = await Person.findById('...Janna id');
    personJanna.age++;
    personJanna.updatedAt = Date.now()
    await personJanna.save()

    let personHulio = await Person.findById('...Hulio id');
    personHulio.age++;
    personHulio.updatedAt = Date.now()
    await personHulio.save()

    let personSancho = await Person.findById('...Sancho id');
    transaction.add(Person, personSancho).update({
        updatedAt: Date.now(),
        __v: ++personSancho.__v
    });

    throw new Error('Test an error - or remark me') // No changes will be saved

    // there must be a return result - and it must be a mongo document
    return personJanna
});

await transaction.commit();