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import {InjectionToken} from '@angular/core'
import {Http} from '@angular/http'
import {Observable} from 'rxjs/Rx'
//simple fn
export function AddDrama(value:string){
return `${value}!!!`
export const AddDramaProvider = {
provide: AddDrama,
useValue: AddDrama //provide the AddDrama fn when it's injected
//complex fn with deps
//export the type signature
export type TransmitDramaFn = (value:string) => Observable<string>
//factory fn - like app.factory() in angularjs
export function DramaTransmitterFactory(http:Http): TransmitDramaFn{
function sendDrama(value:string){
return'', value).map(res => res.json());
return sendDrama;
export const DramaTransmitter:InjectionToken<TransmitDramaFn> = new InjectionToken('DramaTransmitter');
export const DramaTransmitterProvider = {
provide: DramaTransmitter,
useFactory: DramaTransmitterFactory,
deps: [Http, AddDrama]
import { Component, Inject } from '@angular/core';
import { AddDrama, DramaTransmitter, TransmitDramaFn } from './tokens'
selector: 'app-root',
templateUrl: './app.component.html',
styleUrls: ['./app.component.css']
export class AppComponent {
title = 'app';
//use @Inject when not using classes as DI Token
@Inject(AddDrama) addDrama:typeof AddDrama, //typeof or inline - addDrama:(v:string) => string
@Inject(DramaTransmitter) transmit:TransmitDramaFn //use exported type
let dramaHello = addDrama('hello');
import {DramaTransmitterProvider, AddDramaProvider} from './add-drama'
providers: [ DramaTransmitterProvider, AddDramaProvider ]
export class SomeModule {}
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