Injecting Across Frameworks

Angular 1.x providers/services can be upgraded and injected into Angular 2.

Simple Angular 1.x service:

export class A1UpgradeService {
data = 'Hello from Angular 1 service';
}

Simple Angular 2 component that will have an Angular 1.x service injected into it:

import {Component, Inject} from '@angular/core';
import {A1UpgradeService} from '../services/a1-upgrade-service';
@Component({
selector: 'a2-using-a1-service',
template: `<p>{{ message }}</p>`
})
export class A2UsingA1Service {
message = '';
constructor(@Inject('a1UpgradeService') a1UpgradeService:A1UpgradeService) {
this.message = a1UpgradeService.data;
}
}

Attaching everything to Angular 1.x:

import {A2UsingA1Service} from './components/a2-using-a1-service';
import {A1UpgradeService} from './services/a1-upgrade-service';
// Angular 1 Vendor Import
import * as angular from 'angular';
// Import the upgradeAdapter singleton
import {upgradeAdapter} from './upgrade-adapter';
// Name the application
const APPNAME = 'angular-upgrade-example';
// Register classic Angular 1 modules
angular
.module(APPNAME)
.directive('a2UsingA1Service',
upgradeAdapter.downgradeNg2Component(A2UsingA1Service))
.service('a1UpgradeService', A1UpgradeService);

Angular 2.x services can be downgraded and injected into Angular 1. In normal operation, Angular 2.x services would be bootstrapped with the application, but because of ng-upgrade being a hybrid mode, this is not the case. The upgrade adapter comes with an addProvider method that must be used in the interim.

Here is a very simple Angular 2 service:

import {Injectable} from '@angular/core';
@Injectable()
export class A2DowngradeService {
fetchData() {
return 'some data';
}
}

Since Angular 2 is bootstrapped with the upgrade adapter, there is no place to register Angular 2 services. Fortunately the upgrade adapter's addProvider method can do this:

upgradeAdapter.addProvider(Phones);

Lastly, Angular 1.x must be informed about the Angular 2 service:

// The service to downgrade
import {A2DowngradeService} from './services/a2-downgrade'
// Angular 1 Vendor Import
import * as angular from 'angular';
// Import the upgradeAdapter singleton
import {upgradeAdapter} from './upgrade-adapter';
// Name the application
const APPNAME = 'angular-upgrade-example';
// Register classic Angular 1 modules
angular
.module(APPNAME)
.factory('a2DowngradeService',
upgradeAdapter.downgradeNg2Provider(A2DowngradeService));

Using this downgraded service in an Angular 1.x directive is as simple as:

import {A2DowngradeService} from '../services/a2-downgrade';
export function a1UsingA2ServiceDirective() {
return {
restrict: 'E',
scope: {},
bindToController: {},
controller: A1UsingA2,
controllerAs: 'a1UsingA2',
template: `<span>{{ a1UsingA2.message }}</span>`
};
}
class A1UsingA2 {
message: string;
constructor(private a2DowngradeService: A2DowngradeService) {
this.message = this.a2DowngradeService.fetchData();
}
}