CODEWITHSUNDEEP
asynchronoustypescriptdependency-injectioninversion-of-controlinversifyjs
Szymon Dudziak
Szymon Dudziak

Reputation: 542

TypeScript InversifyJS: asynchronous binding

I'm facing this kind of problem: I'm creating Event Manager with ability to handle several concrete providers, and I'm struggling with dependency injection issue here.

I'm using: [email protected], [email protected], [email protected], [email protected]

Lets see that in code:

const socketIO: SocketIO.Server = io.listen(instance);
kernel.bind<SocketIO.Server>(TYPES.SocketIO).toConstantValue(socketIO);

const eventManager: IEventManager = kernel.get<IEventManager>(TYPES.IEventManager);
eventManager.init(kernel.getAll<IEventManagerProvider>(TYPES.IEventManagerProvider));
console.log(eventManager);

And console logs me that event manager is undefined, which crashes the whole app. But... When I disable the kernel.getAll(...) from init, then I'm receiving just what I've expected: 

const eventManager: IEventManager = kernel.get<IEventManager>(TYPES.IEventManager);
eventManager.init([]);
console.log(eventManager);

Gives me: MultipleProvidersEventManager { providers: {} }. The init method is very simple by itself and contains:

@provideSingleton(TYPES.IEventManager)
class MultipleProvidersEventManager { 

    ...

    public init(providers: IEventManagerProvider[]): void {
        forEach(providers, this.registerProvider);
    }

    public registerProvider(provider: IEventManagerProvider): void {
        if (this.providers[provider.type()]) {
            throw new Error('Event Manager provider already registered');
        }
        console.log('Registered ' + provider.type() + ' event manager provider');
        this.providers[provider.type()] = provider;
    }

    ...
}

So my problem is that I have to wait with calling the init method until all required objects are stored properly in InversifyJS container and can be returned. But I don't know how :(. Can someone explain me how should I solve this problem ?

Upvotes: 1

Views: 1183

Answers (1)

Szymon Dudziak
Szymon Dudziak

Reputation: 542

Ok, I've solve it.

The problem was in totally different place that I was thinking on the beginning. So... in MultipleProvidersEventManager class on init method, forEach was loosing the context of the caller. Adding bind soved the problem..

forEach(providers, this.registerProvider.bind(this));

... is the anwser.

Upvotes: 1

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