Angular: Inject an opaque token

Question

I try to understand how I could inject an opaque token.

For instance, I have some service MyService, and I create an opaque token for it:

import {OpaqueToken} from '@angular/core'; 
...
const serviceToken = new OpaqueToken('MyService');
...
providers: [
    {
        provide: serviceToken,
        useValue: 'Service value!'
    }
]

It's ok. But how I could inject this service into my component?

I tried to create the same instance of an Opaque Token in my component and inject it but I got an error: Error: No provider for Token MyService!

Please, you could review an example: Plunker

`constructor(@Inject(serviceToken) private token: string)`? This is covered in the DI docs: https://angular.io/guide/dependency-injection#dependency-injection-tokens. Note that `OpaqueToken` was deprecated and removed. — jonrsharpe, Nov 19 '17 at 11:13
how are you injecting service in your component ? can you show that part too ? — Muhammad Usman, Nov 19 '17 at 11:18
jonrsharpe, I use the same approach you wrote... Error: No provider for Token MyService! — Mike Mameko, Nov 19 '17 at 11:30
Sorry, how I could use the same instancies in module and in a component? — Mike Mameko, Nov 19 '17 at 11:41
yurzui, ok, thanks, I got the idea. The last statement: it is stupid thing to use an opaque token in root module, am I right? — Mike Mameko, Nov 19 '17 at 11:57

score -1 · Answer 1 · answered Nov 19 '17 at 12:04

-1

Conclusion: We could use the same instance of an opaque token in component. Just export it from the module and use in a component.

answered Nov 19 '17 at 12:04

Mike Mameko

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Or create it in a separated file. For example https://github.com/angular/angular/blob/master/packages/core/src/application_tokens.ts – yurzui Nov 19 '17 at 12:07

Angular: Inject an opaque token

1 Answers1