SQL-REPOSITORY

Sql-repository is a simple Knex based implementation of the repository pattern for Node.js. It abstracts access to a given database table with simple methods like load, list or create.

Installation

Simply install the library using :

npm install sql-repository --save

or

yarn add sql-repository

Sql-repository is supposed to work alongside a Knex installation. So please run :

npm install knex --save

or

yarn add knex

How to use

The repository constructor expects 3 parameters :

• an initialized Knex instance
• a table name
• a constructor corresponding to the model

You can directly instanciated a repository like this :

import Repository from 'sql-repository';
import knex from 'knex';

const db = knex({
    client: 'postgresql',
    connection: {
      database: 'myDb',
      host: 'myHost',
      user: 'myUser',
      password: 'myPass',
    },
    migrations: {
      tablename: 'knex_migrations',
    }
  })

class Foo {
  constructor(data) {
    this.id = data.id;
    this.name = data.name;
    this.bar = data.bar;
  }
}

const fooRepository = new Repository(db, 'foo', Foo);

// will generate an array of Foo objects from the content of the foo table
const foos = fooRepository.list();

To avoid repeating yourself it can be useful to create a class inheriting from sql-repository:

class FooRepository extends Repository {
  constructor(db) {
    super(db, 'foo', Foo);
  }
}

const fooRepository = new FooRepository(db);
const foos = fooRepository.list();

The constructor will take two additionnal optionnal parameters:

• dataToPersist: a function allowing you to select which property to persists and how to map it to the database columns.
• formatDataForConstructor: a function allowing you to map data from the database columns to the object expected by your model's constructor.

Example:

const dataToPersist = foo => ({
  name: foo.name,
  bar_id: foo.bar,
});

const formatDataForConstructor = data => ({
  id: data.id,
  name: data.name,
  bar: data.bar_id,
});

const fooRepository = new Repository(db, 'foo', Foo, dataToPersist, formatDataForConstructor);

Methods

Table of Contents

• Repository
  • constructor
  • load
  • list
  • create
  • update
  • delete

Repository

Abstracts CRUD operations with the database, to allow easier implementation of the pattern

constructor

Initialize the Repository

Parameters

• db object The knex instance
• table string The name of the SQL table
• constructor function The constructor for the associated model
• dataToPersist function Tells which data should be persisted in database for a given object (optional, default data=>data)
• formatDataForConstructor function Change data format from database to constructor (ie. start_date -> startDate) (optional, default data=>data)

load

Loads an entity from the given id

Parameters

• id int The object's id

Returns object The corresponding entity

list

Lists the entities

Parameters

• whereClause object Conditions (optional, default {})

Returns array A list of entities

create

Persists a new entity in database

Parameters

• object object The entity to persist

Returns object An entity, with a database generated id

update

Updates an enitity in database

Parameters

• object object The entity to persist in database

Returns boolean True if the operation was a success

delete

Deletes an entity from database

Parameters

• id number The entity's id

Returns boolean True if the operation was a success