Issue with manual Dependency injection in Angular2

Question

I am not sure if it's a bug or I am doing something wrong (prob the latter). I am trying to manually instantiate a component named TodoService.

everything is great on the first 2 steps

var myProvider = new Provider(TodosService, {
  useFactory: (todoAction, http, todoStatsModel, appStore) => {
  return new todoAction(TodoAction, http, todoStatsModel, appStore)
},
  deps: [TodoAction, Http, TodoStatsModel, AppStore]
});
var injector =  Injector.resolveAndCreate([myProvider]);

but blows up when I try to get it so I can use it

var myTodoService = injector.get(TodosService)

am I doing something wrong (possible on the get)?

I wonder why you use a custom injector. This shouldn't be necessary. Sure there are cases but it's better to avoid it if it's not necessary. — Günter Zöchbauer
– Günter Zöchbauer, Commented Feb 14, 2016 at 15:42

Günter Zöchbauer · Accepted Answer · 2016-02-14 15:55:36Z

2

var injector =  Injector.resolveAndCreate([myProvider, TodoAction, Http, TodoStatsModel, AppStore]);

I think you'd be better off not use use a factory with just

var injector =  Injector.resolveAndCreate(
    [TodoService, TodoAction, Http, TodoStatsModel, 
     provide(AppStore, {useValue: new AppStore('')}
     // or
     // provide(AppStore, {useFactory: () => {
     //     return new AppStore('');
     // })
    ]);
var myTodoService = injector.get(TodosService)

edited Feb 14, 2016 at 15:55

answered Feb 14, 2016 at 15:38

Günter Zöchbauer

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6 Comments

born2net Over a year ago

I see now that with your statement I actaully get a more descriptive error, says missing ORIGINAL EXCEPTION: Cannot resolve all parameters for 'AppStore'(?). Make sure that... so I guess I need to resolve more dependencies

Günter Zöchbauer Over a year ago

Exactly. Just add to providers what the AppStore constructor parameter type is.

born2net Over a year ago

I guess this leads to a new issue, my AppStore signature is: constructor(store: any); because it's not an Angular component, just a simple class, so it doesn't really have "dependencies", just need to be passed in a value... mmm.... possible?

Günter Zöchbauer Over a year ago

This is a perfect case for creating a new Provider() (or using provide()) while it doesn't look like TodosService needs a provider.

born2net Over a year ago

going down the rabbit hole... it now compians it needs ConnectionBackend so I added, and now it complains that it needs RequestOptions so I added... and now it complains that: ORIGINAL EXCEPTION: Cannot resolve all parameters for 'RequestOptions'(?). Make sure tha.... which has a constructor signtaure of: 'constructor({method, headers, body, url, search}?: RequestOptionsArgs);' :( never ending...

|

born2net · Accepted Answer · 2016-02-14 16:27:54Z

Tx to Günter Zöchbaue who solved this for me... he is the man!!!

here is the code for everyone else:

constructor(private appStore:AppStore) {
    super();
}

private factoryService(){
    if (this.service)
        return;
    var injector = Injector.resolveAndCreate(
        [
            TodosService,
            TodoAction,
            HTTP_PROVIDERS,
            TodoStatsModel,
            provide(AppStore, {useValue: this.appStore})
        ]);

    this.service = injector.get(TodosService);
    service.sayHello('Sean');
}

basically manually creating "TodoService" Angular2 component through multiple dependencies (and even one vanilla non component (class) AppStore) and all via the injector... wooof...!

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