typedi

What is typedi?

TypeDI is a dependency injection tool for TypeScript and JavaScript. It allows you to manage the lifecycle and dependencies of your services and components in a clean and efficient way.

What are typedi's main functionalities?

Service Decorator

The `@Service` decorator is used to mark a class as a service that can be injected. The `Container.get` method is then used to retrieve an instance of the service.

```typescript
import { Service } from 'typedi';

@Service()
class ExampleService {
  sayHello() {
    return 'Hello, World!';
  }
}

const exampleService = Container.get(ExampleService);
console.log(exampleService.sayHello()); // Output: Hello, World!
```

Inject Decorator

The `@Inject` decorator is used to inject a dependency into a class. In this example, `DependencyService` is injected into `MainService`.

```typescript
import { Service, Inject } from 'typedi';

@Service()
class DependencyService {
  getValue() {
    return 'Dependency Value';
  }
}

@Service()
class MainService {
  constructor(@Inject(() => DependencyService) private dependencyService: DependencyService) {}

  getValue() {
    return this.dependencyService.getValue();
  }
}

const mainService = Container.get(MainService);
console.log(mainService.getValue()); // Output: Dependency Value
```

Container

The `Container` class is used to manage the lifecycle of services. You can manually set and get instances of services using `Container.set` and `Container.get`.

```typescript
import { Container } from 'typedi';

class ExampleService {
  sayHello() {
    return 'Hello, World!';
  }
}

Container.set(ExampleService, new ExampleService());
const exampleService = Container.get(ExampleService);
console.log(exampleService.sayHello()); // Output: Hello, World!
```

Other packages similar to typedi

inversify

Inversify is a powerful and flexible inversion of control (IoC) container for JavaScript and TypeScript. It provides a similar feature set to TypeDI, including decorators for services and dependency injection. Inversify is known for its extensive documentation and strong community support.

tsyringe

TSyringe is a lightweight dependency injection container for TypeScript. It offers a similar decorator-based API for defining and injecting services. TSyringe is designed to be simple and easy to use, making it a good choice for smaller projects or those new to dependency injection.

awilix

Awilix is a dependency injection container for JavaScript and TypeScript that focuses on developer experience and ease of use. It provides a fluent API for defining and resolving dependencies, and supports both class-based and function-based services. Awilix is known for its flexibility and ease of integration with various frameworks.

README

TypeDI

Dependency injection tool for Typescript.

Usage

If you simply want to use a container:

class SomeClass {

    someMethod() {
    }

}

let someClass = Container.get<SomeClass>(SomeClass);
someClass.someMethod();

If you want to inject other classes into your service you can do:

class BeanFactory {
    create() {
    }
}

class SugarFactory {
    create() {
    }
}

class WaterFactory {
    create() {
    }
}

class CoffeeMaker {

    @Inject()
    beanFactory: BeanFactory;
    
    @Inject()
    sugarFactory: SugarFactory;
    
    @Inject()
    waterFactory: WaterFactory;

    make() {
        this.beanFactory.create();
        this.sugarFactory.create();
        this.waterFactory.create();
    }

}

let coffeeMaker = Container.get<CoffeeMaker>(CoffeeMaker);
coffeeMaker.make();

If you want to use constructor injection:

class BeanFactory {
    create() {
    }
}

class SugarFactory {
    create() {
    }
}

class WaterFactory {
    create() {
    }
}

@Service()
class CoffeeMaker {

    private beanFactory: BeanFactory;
    private sugarFactory: SugarFactory;
    private waterFactory: WaterFactory;

    constructor(beanFactory: BeanFactory, sugarFactory: SugarFactory, waterFactory: WaterFactory) {
        this.beanFactory = beanFactory;
        this.sugarFactory = sugarFactory;
        this.waterFactory = waterFactory;
    }

    make() {
        this.beanFactory.create();
        this.sugarFactory.create();
        this.waterFactory.create();
    }

}

let coffeeMaker = Container.get<CoffeeMaker>(CoffeeMaker);
coffeeMaker.make();

That's should be enough to use a proper dependency injection. Also you can inject a modules that you want to require:

class SomeClass {
    someMethod() {
    }
}

@Service()
class CoffeeMaker {

    private someClass: SomeClass;
    private gulp: any; // you can use type if you have definition for this package

    constructor(someClass: SomeClass, @Require('gulp') gulp: any) {
        this.someClass = someClass;
        this.gulp = gulp; // the same if you do this.gulp = require('gulp')
    }

    make() {
        this.someClass.someMethod();
        console.log(this.gulp); // here you get console.logged gulp package =)
    }
}

let coffeeMaker = Container.get<CoffeeMaker>(CoffeeMaker);
coffeeMaker.make();

Take a look on samples in ./sample for more examples of usages.

Todos

• cover with tests