Nodesmith Core

The core package provides foundational features for building modular, event-driven Node.js applications. It includes:

• Dependency Injection (DI) Container
• Event Bus
• Module Loader
• Type Definitions for Modules

Installation

npm install @yourorg/core

Features

1. Dependency Injection (DI) Container

A simple, class-based DI container for registering and resolving dependencies.

Register a class:

import { container } from '@yourorg/core';

container.register('EmailService', EmailServiceClass, { singleton: true });

Resolve a class:

const emailService = container.resolve<EmailService>('EmailService');

• Supports singleton and transient lifecycles.
• All dependencies are registered and resolved by string keys.

2. Event Bus

A lightweight event bus for decoupled communication between modules.

Usage:

import { container, EventBus } from '@yourorg/core';

// Register EventBus as a singleton in the DI container
container.register('EventBus', EventBus, { singleton: true });

// Resolve the singleton EventBus instance
const eventBus = container.resolve<EventBus>('EventBus');

// Listen for events
eventBus.on('user.created', (user) => {
  console.log('User created:', user);
});

// Emit events
eventBus.emit('user.created', { id: 1, name: 'Alice' });

• Register and remove event handlers.
• Emit events with arbitrary payloads.
• Always resolve the EventBus from the DI container to ensure a single shared instance.

3. Module Loader

Automatically loads enabled modules based on your config/modules.json file.

Usage:

import { loadEnabledModules } from '@yourorg/core';

const modules = loadEnabledModules();

• Scans the modules/ directory for modules with a module.json manifest.
• Automatically enables new modules and removes stale ones.
• Validates module dependencies and migration files.

4. Type Definitions

TypeScript interfaces for module manifests and lifecycle hooks.

Example:

import { ModuleManifest, LoadedModule, NodesmithModuleHooks } from '@yourorg/core';

• ModuleManifest: Describes a module’s metadata, dependencies, and assets.
• LoadedModule: Represents a loaded module with its manifest and path.
• NodesmithModuleHooks: Lifecycle hooks for modules (init, registerRoutes, registerModels, onShutdown).

Example: Registering and Using the Event Bus via DI

import { container, EventBus } from '@yourorg/core';

// Register EventBus as a singleton
container.register('EventBus', EventBus, { singleton: true });

// Resolve and use
const eventBus = container.resolve<EventBus>('EventBus');
eventBus.emit('app.started');

Directory Structure

core/
  di/
    container.ts
  events/
    eventBus.ts
  loaders/
    moduleLoader.ts
  types/
    index.ts
  index.ts
  package.json

Contributing

Feel free to open issues or PRs to improve the core features!