6. Repositories

Introduction to the repository concept

A repository is a design pattern intended to decouple database code from your business logic.

This pattern bring some important benefits. First, makes your code easier to read and maintain, because database code is not spread throughout application. Second, the code becomes significantly easier to unit test. Its be easily mock repositories while testing your business logic instead of having to set up databases, tables and seeding them with data. And third, the business logic does not depend strongly on a specific database platform.

After herbs update run, its automatic create inside src/infra/data/database/repositories a repository file for each entity we previous created.

These repositories files abstract knex.js to make queries in database and any class created in these files will be exported for herbarium.repositories, so we will can access theses repositories inside any place in our application importing herbarium.

itemRepository.js

A repository file it should be like:

// src/infra/data/database/repositories/itemRepository.js

const { Repository } = require("@herbsjs/herbs2knex")
const { herbarium } = require('@herbsjs/herbarium')
const Item = require('../../../domain/entities/item')
const connection = require('../database/connection')

class ItemRepository extends Repository {
    constructor(injection) {
        super({
            entity: Item,
            table: "items",
            knex: connection
        })
    }
}

module.exports =
    herbarium.repositories
        .add(ItemRepository, 'ItemRepository')
        .metadata({ entity: Item })
        .repository