repositoryBuilder

Takes a reducer and an adapter and returns a repository. A repository is the layer of our Onion Architecture (see Introduction) which handles data persistence.

The write-model repository has a single method called getById. When invoked, it uses the adapter to load all events for given ID and runs them through the reducer to calculate the current state. It returns an object that contains state and also a save method, which is used to append new events.

Methods

build

build({ adapter, reducer })

builds a repository

Parameters

attribute

type

description

adapter

object

Any object which implements the write-model Adapter Interface.

reducer

function

a function which, given a list of events, knows how to calculate the current state of an object.

Returns

{ getById } - an object with the getById function.

getById

getById(id)

Loads and returns the current state of an entity. Also returns a save function for appending new events to the data store.

Parameters

attribute

type

description

id

string

the id of the entity

Returns

{ state, save } - an object containing an arbitrary state object, and a save function.

save

save(events)

Appends new events to the datastore

Parameters

attribute

type

description

events

array

an array of arbitrary event objects

Returns

null