fl-node-di v0.0.6
Hierarchical NodeJS dependency injection inspired by Angular
See this library in action with this stackblitz demo.
Installation
Add the package to your project
npm i --save fl-node-di
# or
yarn add fl-node-diImport the decorators with
import { FlModule, Component, Injectable, Inject } from 'fl-node-di'Usage
NodeJS dependency injection module on top of inversify for using backend DI in a way similar to Angulars DI. E.g. you can use the following snippet throughout your complete application
@FlModule({
imports: [ AuthModule, Http2Module ],
declarations: [ AppComponent ],
providers: [ AuthService ],
exports: [ ]
})
export class AppModule {}The other two decorators are
@Component()
export class AppComponent {
constructor (@Inject(AuthService) authService: AuthService) {}
}which treats the decorator as an inversify @injectable and directly creates an instance when the
parent module gets instanciated. The other one is the @Injectable() decorator
@Injectable()
export class AuthService {}which returns an inversify @injectable decorator, but does not directly creates an instance but
instanciates itself when an @Inject(serviceIdentifier) is used as a constructor parameter in the
same or a childs containers class.
The DI system is hierarchical.
Cheatsheet
The decorators:
| Decorator | Description | Parameters | Return value |
|---|---|---|---|
@FlModule() | Creates a container where the classes are stored, imports child-FlModules | config: { imports?: any[], declarations?: any[], providers?: any[], exports?: any[] } | Returns a custom decorator where a container object is created in the constructor |
@Injectable() | Make class bindable to an FlModules container | - | Inversify @injectable() |
@Component() | Make class bindable to an FlModules container | - | Inversify @injectable() |
@Inject(serviceIdentifier) | Let the DI know that a class instance is needed, if not exist, create class | serviceIdentifier | - |
The @FlModule() parameters:
| Input parameter | Description |
|---|---|
| imports | Creates an instance of the imported FlModule(), reads the exports parameter of the instantiated object and stores the exports in its own container. The instance is handled as a child of this module, so Inject()s will work in the child even if the child does not contain the instance itself, but its parent. |
| declarations | Binds @Component() decorated classes to the container and after creating all imports it directly creates an instance. |
| providers | Binds @Injectable() decorated classes to the container |
| exports | Binds @Injectable() or @Component() decorated classes to the parents container |