eventre

eventre

Event Sourcing Framework in MongoDB

Usage

import { eventre } from "eventre";
import { MongoClient } from "mongodb";

const mongoClient = new MongoClient();
const db = mongoClient.db("my_database");

/**
 * 1. Define your domain event
 */
type MyDomainEvent =
  | BaseDomainEvent<
      "init",
      {
        // ...
      }
    >
  | BaseDomainEvent<
      "update",
      {
        // ...
      }
    >;

/**
 * 2. Define your state
 */
type MyState = {
  // ...
};

/**
 * 3. Implement your own business logic clearly in reducer
 */
const reducer: BaseReducer<MyDomainEvent, MyState> = (prevState, event) => {
  // ...
};

/**
 * 4. Then, `eventre` automatically make common repository interface
 */
const repository = eventre({
  db,
  aggregateName: "MyModel",
  reducer,
});

// Scan all aggregates
repository.all();

// Find one aggregate with `aggregateId`
repository.findOne({
  aggregateId: "...",
});

// Find many aggregates with `aggregateIds`
repository.batchGet({
  aggregateIds: ["...", "..."],
});

// Create aggregate with initial DomainEvent
repository.create({
  initialEventName: "init",
  initialEventData: {
    // ...
  },
});

// Dispatch DomainEvent to aggregate
repository.dispatch({
  aggregate,
  eventName: "edit",
  eventData: {
    // ...
  },
});