decorators.md

Decorators

Decorators provider you with a way to register and resolve your dependencies. Behind the scenes, it will interact with our dependency injection container.

We currently support two decorators:

• @Injectable
• @Inject

You can also work directly with the dependency injection container.

@Injectable

The @Injectable decorator marks a class as injectable and registers it with the dependency injection container.

Usage

import { Injectable } from '@rafaeljcamara/xinjects';

@Injectable()
class MyService {
  // ...
}

You can also pass a IInjectableConfiguration configuration object to the @Injectable decorator.

import { Injectable } from '@rafaeljcamara/xinjects';

@Injectable({
    lifetime: Lifetime.Transient,
    token: "MyServiceCustomToken"
})
class MyService {
  // ...
}

More informations about this configuration object can be found here.

@Inject

The @Inject allows you to resolve a given dependency.

There are currently two ways to resolve a dependency:

1. Property injection
2. Constructor injection

To properly inject something with the @Inject decorator, you can do one of the following:

1. Pass nothing to the @Inject decorator and it will determine the type of dependency to inject. Example:

import { Inject } from '@rafaeljcamara/xinjects';

class MyClass{
    @Inject()
    dependency: MyService;
}

2. Provide a string injection token that you have configured the dependency with (when using the @Injectable decorator). Example:

import { Inject } from '@rafaeljcamara/xinjects';

class MyClass{
    @Inject("MyServiceCustomToken")
    dependency: MyService;
}

3. Provide the class to inject, if you haven't configured any injection token while using the @Injectable decorator. Example:

import { Inject } from '@rafaeljcamara/xinjects';

class MyClass{
    @Inject(MyService)
    dependency: MyService;
}

Property injection

Example:

import { Inject } from '@rafaeljcamara/xinjects';

class MyClass{
    @Inject()
    dependency: MyService;
}

Constructor injection

Example:

import { Inject } from '@rafaeljcamara/xinjects';

class MyClass {
    constructor(@Inject() public dependency: MyService) {}
}

⚠️ Using decorators

To properly work and enable the usage of our decorators there are a couple of things you need to have in consideration.

1. You must be working with TypeScript.
2. You must enable these two properties in your tsconfig.json file:

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