Di
Dependency Injection in ~800 bytes
Installation:
npm i @lit-kit/diExample:
import { Injector, Inject } from '@lit-kit/di';
class FooService {
sayHello() {
return 'Hello From FooService';
}
}
class BarService {
constructor(@Inject(FooService) private foo: FooService) {}
sayHello() {
return 'Hello From BarService and ' + this.foo.sayHello();
}
}
const app = new Injector();
app.get(BarService).sayHello(); // Hello from BarService and Hello from FooServiceOverride A Service:
import { Injector, Inject } from '@lit-kit/di';
class FooService {
sayHello() {
return 'Hello From FooService';
}
}
class BarService {
constructor(@Inject(FooService) private foo: FooService) {}
sayHello() {
return 'Hello From BarService and ' + this.foo.sayHello();
}
}
// Override FooService with an alternate implementation
const app = new Injector({
providers: [
{
provide: FooService,
useClass: class extends FooService {
sayHello() {
return 'IT HAS BEEN OVERRIDEN'
}
}
}
]
});
app.get(BarService).sayHello(); // Hello from BarService and IT HAS BEEN OVERRIDENRoot Service
If you have nested injectors and you still want singleton instances decorator your services with @Service()
import { Service } from '@lit-kit/di';
@Service()
class FooService {
sayHello() {
return 'Hello From FooService';
}
}Inject services with custom decorators:
import { Injector, Inject } from '@lit-kit/di';
function FooRef(c: any, k: string, i: number) {
Inject(FooService)(c, k, i)
}
class FooService {
sayHello() {
return 'Hello From FooService';
}
}
class BarService {
constructor(@FooRef private foo: FooService) {}
sayHello() {
return 'Hello From BarService and ' + this.foo.sayHello();
}
}
// create a new instance of our injector
const app = new Injector();
app.get(BarService).sayHello(); // Hello from BarService and Hello from FooService