Skip to main content

Core Concepts

The @tarpit/core module is the foundation of the Tarpit framework. It provides the essential dependency injection system, decorator-based architecture, and platform management that powers all Tarpit applications.

Overview​

Tarpit's core is built around several key concepts:

  • Dependency Injection - Automatic resolution and injection of dependencies
  • Decorators - TypeScript decorators for marking classes and methods
  • Platform - The main application container and lifecycle manager
  • Providers - Various ways to provide dependencies to the DI system
  • Built-in Services - Core services like logging, configuration, and event handling
Examples Repository

Working examples for core concepts can be found in example/core/.

Installation​

npm install @tarpit/core reflect-metadata
Why reflect-metadata?

reflect-metadata is required for TypeScript decorator metadata reflection. Tarpit's dependency injection system uses this to automatically detect constructor parameter types and enable type-safe dependency resolution.

TypeScript Configuration Required

Tarpit requires TypeScript decorators. Make sure your tsconfig.json includes:

{
  "compilerOptions": {
    "experimentalDecorators": true,
    "emitDecoratorMetadata": true
  }
}

Quick Example​

Complete Example

example/core/quick-start.ts

Here's a minimal example showing the core concepts in action:

import { Platform, TpService, TpModule } from '@tarpit/core'

// A simple service
@TpService()
class GreetingService {
    greet(name: string) {
        return `Hello, ${name}!`
    }
}

// A module that provides the service
@TpModule({
    providers: [GreetingService]
})
class AppModule {
    constructor(private greeting: GreetingService) {}
    
    start() {
        console.log(this.greeting.greet('World'))
    }
}

// Platform bootstraps everything
new Platform()
    .import(AppModule)
    .start()

Next Steps​

Explore the core concepts in detail: