Angular 2 - No provider for Service

Question

I've been trying to troubleshoot a strange problem with angular 2 where it isn't detecting my provider declaration, but nothing is working. I can't even replicate it in plunkr.

I'm using angular 2 rc 3 with router 3.0 alpha.8.

Error message is: ORIGINAL EXCEPTION: No provider for TestService!

app.routes.ts:

import { provideRouter, RouterConfig } from '@angular/router';

import { HomeComponent } from './app/home/home.component';
import { LogInComponent } from './app/log-in/log-in.component';
import { SignUpComponent } from './app/sign-up/sign-up.component';

export const routes: RouterConfig = [
  { path: '', component: HomeComponent },
  { path: 'log-in', component: LogInComponent },
  { path: 'sign-up', component: SignUpComponent }
];

export const APP_ROUTER_PROVIDERS = [
  provideRouter(routes)
];

main.ts:

import { bootstrap }    from '@angular/platform-browser-dynamic';
import { enableProdMode } from "@angular/core";

import { AppComponent } from './app/app.component';
import { APP_ROUTER_PROVIDERS } from './app.routes';

// enableProdMode();

bootstrap(AppComponent, [
  APP_ROUTER_PROVIDERS
])
.catch(error => console.log(error));

app/app.component.ts:

import { Component } from '@angular/core';
import { ROUTER_DIRECTIVES } from '@angular/router';

import { TestService } from './shared/test.service';

@Component({
  selector: 'my-app',
  template: `
    <div id="menu">
      <a [routerLink]="['/sign-up']"><button>Sign Up</button></a>
    </div>
    <router-outlet></router-outlet>
  `,
  directives: [ROUTER_DIRECTIVES],
  providers: [TestService]
})
export class AppComponent {

  constructor() { }

}

app/sign-up/sign-up.component.ts:

import { Component } from '@angular/core';
import { ROUTER_DIRECTIVES } from '@angular/router';

import { TestService } from '../shared/test.service';

@Component({
  selector: 'sign-up',
  template: `<h1>Sign up!</h1>`,
  directives: [ROUTER_DIRECTIVES]
})
export class SignUpComponent {
  constructor(private testService: TestService) {
    this.testService.test('works?');
  }


}

app/shared/test.service.ts:

import { Injectable } from '@angular/core';

@Injectable()
export class TestService {

  constructor() { }

  test(message: string) {
    console.log(message);
  }

}

So, I'm providing the testservice in the base component (app.component.ts) because I want all my components to access the same instance. However, when I navigate to sign-up, I get the no provider for testservice error. If I provide the TestService within the sign-up component, this then works:

import { Component, OnInit } from '@angular/core';
import { ROUTER_DIRECTIVES } from '@angular/router';

import { TestService } from '../shared/test.service';

@Component({
  selector: 'sign-up',
  template: `<h1>Sign up!</h1>`,
  directives: [ROUTER_DIRECTIVES],
  providers: [TestService]
})
export class SignUpComponent implements OnInit {
  constructor(private testService: TestService) { }

  ngOnInit() { }

}

However, I need the same instance accessible throughout my app, so how can I inject this at the main component level?

I even tried replicating this app-level service providing with plunkr with the same version of everything, but it doesn't seem to give me the same error...

http://plnkr.co/edit/5bpeHs72NrlyUITCAJim?p=preview

Solution 1

It was a configuration issue after all, and a completely elusive one at that.

Per the ang2 style guide, I had my main.ts one folder up from my main app folder, and in systemjs.config I had to declare the main for app as '../main.js'. When I moved the main file to the root app folder and changed the package declaration in systemjs to 'main.js' it worked.

The odd thing is everything else worked, right up until I try to utilize hierarchical dependency injection.

Solution 2

To All future readers - and this is correct for angular 2.0.0 rc-4:

make sure that you follow the below folder structure:

root:
index.html
package.json
systemjs.config.js
tsconfig.json (if using TypeScript) 
typings.json
app (folder):
 - main.js (the root script for your app)
 - app.component.js (the root component for the entire app)

This is crucial for the hierarchical injection to properly scope and identify providers.

Also, and this is very important - if still encountering problems and you are using TypeScript or any other transpiled language- delete any artifacts which your transpiler produces for every associated class in the problematic object graph - this, and the OP's answer eventually helped in my case (*.map.js and *.js files deleted and re-transpiled).

Solution 3

For me, some references to the "services" folder were "Services". When I made them all "services" (lower case), it worked.

For example:

import {ApiService} from "./Services/api.service";

didn't work, but this worked:

import {ApiService} from "./services/api.service";

Solution 4

Injecting something on the app level is done in bootstrap:

main.ts:

import { TestService } from '../shared/test.service';

bootstrap(AppComponent, [
  APP_ROUTER_PROVIDERS, TestService
])

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