@noddde/core

TypeScript types and definitions for DDD, CQRS, and Event Sourcing using the functional Decider pattern.

Documentation | GitHub

Install

yarn add @noddde/core
# or
npm install @noddde/core

What's Inside

@noddde/core is the foundation of the noddde framework. It provides:

• Aggregate definitions (defineAggregate) with the Decider pattern: initialState, decide, evolve
• Saga definitions (defineSaga) for orchestrating cross-aggregate workflows as pure functions
• Projection definitions (defineProjection) for building read models from event streams
• Domain definitions (defineDomain) — a pure, sync identity function that captures the structural shape of a domain (aggregates, projections, sagas, handlers) without any runtime or infrastructure
• CQRS abstractions for command and query buses, handlers, and typed messages
• Event-driven types for event buses, event handlers, and domain events with metadata
• Persistence interfaces for event-sourced and state-stored strategies
• Infrastructure contracts for locking, snapshots, outbox, idempotency, and unit of work

Zero runtime dependencies. Strict TypeScript with full type inference.

Usage

import {
  defineAggregate,
  type DefineCommands,
  type DefineEvents,
  type Infrastructure,
} from "@noddde/core";

type BankAccountEvent = DefineEvents<{
  DepositMade: { amount: number };
  WithdrawalMade: { amount: number };
}>;

type BankAccountCommand = DefineCommands<{
  Deposit: { amount: number };
  Withdraw: { amount: number };
}>;

type BankAccountDef = {
  state: { balance: number };
  events: BankAccountEvent;
  commands: BankAccountCommand;
  infrastructure: Infrastructure;
};

const BankAccount = defineAggregate<BankAccountDef>({
  initialState: { balance: 0 },

  decide: {
    Deposit: (command, state) => ({
      name: "DepositMade",
      payload: { amount: command.payload.amount },
    }),
    Withdraw: (command, state) => {
      if (state.balance < command.payload.amount) {
        throw new Error("Insufficient funds");
      }
      return {
        name: "WithdrawalMade",
        payload: { amount: command.payload.amount },
      };
    },
  },

  evolve: {
    DepositMade: (payload, state) => ({
      balance: state.balance + payload.amount,
    }),
    WithdrawalMade: (payload, state) => ({
      balance: state.balance - payload.amount,
    }),
  },
});

Related Packages

| Package | Description | | :----------------------------------------------------------------- | :--------------------------------------------------------------------- | | @noddde/engine | Runtime engine with domain orchestration and in-memory implementations | | @noddde/testing | Test harnesses for aggregates, sagas, projections, and domains | | @noddde/drizzle | Drizzle ORM persistence adapter | | @noddde/prisma | Prisma persistence adapter | | @noddde/typeorm | TypeORM persistence adapter |

License

MIT