sequelize-repository

sequelize-repository is a simple implementation of the repository pattern for sequelize

Table of contents

• SQRepository
• Query Methods
• Criteria
• TransactionRunner

SQRepository

The SQRepository is the entry point to the library, it contains all repository methods, you must extend from this class to use it.

Example:

class MyRepository extends SQRepository {
    constructor() {
        super(MyRepository, db.MyModel, 'my_id' })
    }
}

const repository = new MyRepository()

const entities = await this.repository.findById(1)

The SQRepository contains the following methods:

save(model,t)
findAll()
findAllWhere(query)
findAllByCriteriaAndPaginated({criteria, page, size, orderAttr})
findAndCountAll({condition, order, page, size, include})
findOne(query)
findById(id)
sum(field, criteria)

Query-Methods

The Query methods api is an easy way to generate simple queries without almost any code. You just have to write the method signature and parameters and SQRepository will autogenerate the required code for you.

Keyword	Sample	Sequelize Snippet	Returns
And	findAllByNameAndRole	model.findAll({ where: { name, role }, include: { all: true } })	[{entity}]
Paginated	findByNamePaginated	model.findAndCountAll({ where: { name }, limit, offset, include: { all: true } })	{ totalItems: 10, rows: [{entity}], totalPages: 15, currentPage: 0 }

NOTE: The following keywords are going to be added in future releases:

• Or
• Any
• Exists
• Between

Example:

class MyRepository extends SQRepository {
    constructor() {
        super(MyRepository, db.MyModel, 'my_id' })
    }
    async findAllByNameAndEmail(name,email) {}
}

const repository = new MyRepository()
    
const entities = await this.repository.findAllByNameAndEmail("John", "[email protected]")

Criteria

Criteria is a class that represents sequelize queries in a simpler way, the CriteriaBuilder is used to build complex criterias easily. There are methods of the repository that expect a Criteria Object Examples:

const { Op } = require('sequelize')
const criteria = new Criteria([{ field: 'client_id', value: 1234, condition: { [Op.eq]: 1234 }])
criteria.getCriteria() // -> { client_id: { [Op.eq] : 1234 } }
await myRepository.findAllWhere(criteria) // -> [{ client_id: 1234 }]

const builder = new CriteriaBuilder()
const criteria = builder.add('client_id', clientId, { [Op.eq]: clientId })
   .add('created_date', fromDate, { [Op.eq]: clientId })
   .add('status', 'FAILURE', { [Op.ne]: 'FAILURE' })
   .add('request_id', null, { [Op.ne]: null })
   .build()
criteria.getCriteria() // { client_id:  { [Op.eq]: 1234 }, created_date: { [Op.eq]: 10/10/2021 } ...}

TransactionRunner

The transaction runner is a solution to handle the sequelize transactions in just one place. In order to use the "save" method of the repository you must execute it inside a transaction. Example:

const db = require('../models')
const result = await TransactionRunner.run(db, async (t) => {
    const entity = await repository.save({ id: 1, name: 'John', lastName: 'Doe' }, t)
    return entity
})

Ideally you would wrap this runner to not import the db across many different files and just have it in one place

const db = require('../models')

const runTransaction = async (callback) => {
    const result = await TransactionRunner.run(db, callback);
    return result;
} 

import { runTransaction } from 'wrapper'

const result = await runTransaction(async (t) => {
    const entity = await repository.save({ id: 1, name: 'John', lastName: 'Doe' }, t)
    return entity;
})