TSyringe Dependency Injection Tutorial

Introduction

This repository contains a step-by-step guide on using TSyringe for dependency injection in a TypeScript project. TSyringe is a powerful and easy-to-use dependency injection library that helps create modular, maintainable, and testable code.

Project Structure

src/
├── services/
│   ├── EmailService.ts
│   └── NotificationService.ts
├── main.ts

Getting Started

Prerequisites

• Node.js installed
• npm installed

Installation

1. Clone the repository:

   git clone https://github.com/yourusername/tsyringe-tutorial.git
   cd tsyringe-tutorial

2. Install dependencies:

   npm install

3. Initialize TypeScript configuration (if not already done):

   npx tsc --init

4. Configure tsconfig.json:

   Make sure the following options are enabled in your tsconfig.json:

   {
     "compilerOptions": {
       "target": "es6",
       "module": "commonjs",
       "outDir": "./dist",
       "rootDir": "./src",
       "strict": true,
       "esModuleInterop": true,
       "experimentalDecorators": true,
       "emitDecoratorMetadata": true
     },
     "include": ["src"]
   }

Usage

1. Build the project:

   npx tsc

   This will compile your TypeScript files into JavaScript and place them in the dist directory.

2. Run the project:

   node dist/main.js

   You should see the following output:

   Email sent with message: Hello, Dependency Injection with TSyringe!
   

Code Overview

EmailService.ts

import 'reflect-metadata';
import { injectable } from 'tsyringe';

@injectable()
class EmailService {
  sendEmail(message: string) {
    console.log(`Email sent with message: ${message}`);
  }
}

export default EmailService;

NotificationService.ts

import { inject, injectable } from 'tsyringe';
import EmailService from './EmailService';

@injectable()
class NotificationService {
  constructor(
    @inject('EmailService') private emailService: EmailService
  ) {}

  sendNotification(message: string) {
    this.emailService.sendEmail(message);
  }
}

export default NotificationService;

main.ts

import 'reflect-metadata';
import { container } from 'tsyringe';
import EmailService from './services/EmailService';
import NotificationService from './services/NotificationService';

// Register the EmailService with the container
container.register('EmailService', { useClass: EmailService });

// Resolve the NotificationService, which has a dependency on EmailService
const notificationService = container.resolve(NotificationService);

// Use the NotificationService to send a notification
notificationService.sendNotification('Hello, Dependency Injection with TSyringe!');

Contributing

Feel free to fork this repository, make improvements, and submit a pull request. Any contributions are welcome!

License

This project is licensed under the MIT License.