Modules

Everything is exported from effect-cqrs as a namespace, as in import { Aggregate, ViewModel } from "effect-cqrs", and each module also has its own path, such as effect-cqrs/ViewModel.

Aggregate

Defines aggregates. Source

Export	What it is
make<State>()({ name, events, initial, projection })	Starts an aggregate, to which .command(name, { payload, handler }) adds commands
evolve(aggregate, state, event, meta)	Applies one event with the aggregate’s projection
EventMeta, CommandContext	What projections and handlers receive besides the event or payload
State, Event, CommandName, Payload, CommandError, Context	Types derived from an aggregate

AggregateService

Runs an aggregate against the event store. Source

Export	What it is
make(aggregate, { maxRetries, stateCacheSize })	The service: commands, dispatch, readModel, history
CommandResult, HistoryEntry	What a command and history return
UnknownCommand, InvalidCommand, EventDecodeError	Its errors, besides the store’s
makeEventDecoder, makeEventEncoder	Convert between stored JSON and an aggregate’s events

ViewModel

Projects events into read models. Source

Export	What it is
make({ name, aggregates, handlers, dispose })	Defines a view model
layer([...])	Runs view models in the background and provides ViewModels
ViewModels	The service: replay, caughtUp, status
ViewModelError, UnknownViewModel	A handler’s failure, and a replay of an unknown name

EventStore

The append-only log. Source

Export	What it is
EventStore	The service: append, read, subscribe, head, changes
layerMemory, makeMemory	The store in memory
make(backend), Backend	Builds a store on another database
StoredEvent, EventFilter, AppendInput	What it stores, selects and takes
ConcurrencyConflict, EventStoreError	Its errors

Checkpoints

How far each view model has read. Source

Export	What it is
Checkpoints	The service: get and set
layerMemory	Checkpoints in memory

SqliteEventStore and PostgresEventStore

Durable stores through effect/sql. SQLite, PostgreSQL

Export	What it is
layer(options)	The event store, given a SqlClient
layerCheckpoints(options)	Checkpoints in the same database
Options	eventsTable and checkpointsTable

Fixture

Tests an aggregate. Source

Export	What it is
make(aggregate)	A fixture: givenEvents, when, whenFails, inspectState
Scenario, Outcome	The chain, and what yielding it gives
ExpectationFailed	The defect a failed expectation raises