ts-inject

A lightweight, type-safe dependency injection library for TypeScript.

ts-inject simplifies dependency management in TypeScript applications by providing a straightforward and efficient way to inject dependencies, enhancing modularity and testability.

✨ Features

• Type-Safe: Leverages TypeScript's type system for compile-time safety.
• Lightweight: Minimal overhead with a focus on simplicity.
• Flexible: Supports various injection patterns to suit different needs.
• Test-Friendly: Facilitates easy mocking and testing of dependencies.

📦 Installation

npm install @michaelganchas/ts-inject
# or
yarn add @michaelganchas/ts-inject

📌 Where to Use

You can use ts-inject in any TypeScript-based project where clean architecture, testability, and modularity matter. Some common use cases include:

• Modular backend applications (e.g. Node.js with Express or Koa)
• Domain-driven design (DDD) implementations
• Microservices and serverless functions
• CLIs and tooling built with TypeScript
• Unit testing with easily mockable dependencies
• Frontend apps (e.g. React, React Native or Vue with TypeScript) that follow service-based architecture

If you're tired of manually wiring dependencies or passing instances all over your codebase, ts-inject offers a clean, intuitive alternative.

🔍 Examples

• Using the container to register and obtain dependencies:

  • First we define our implementation

  [src/services/events/eventsService.ts]
    
  const send = () => {...}
  
  export const eventsService = {
      send,
  };
  
  export type EventsService = typeof eventsService;

  • Then, we set up a key for that implementation

  [src/services/events/types.ts]
    
  export const EventsServiceKey: PropertyKey = 'EVENTS_SERVICE';

  • We hook everything up together

  [src/services/events/index.ts]
    
  container.register<EventsService>(EventsServiceKey, () => eventsService);

  • Then we're just missing two things:
    • A place to import/load all the registrations

    [src/core/di/diSetup.ts]
          
    import '/src/services/events/index';
    ...

    • And lastly, to run it in our App's entry point as one of the first imports

    [src/index.ts]
          
    import 'src/core/di/diSetup';
    ...

• Auto wire dependencies automatically:

  • Check the examples/ folder for how to use for either Class injections, or functional ones.

📚 API Reference

Check the types.ts file under src/ as it contains all the explanations inside their definitions.