Class Observer<EventName>

This is a simple observer implementation for implementing synchronous in-process events for a local service.

You can use it like this:

enum FooEvent {
    CHANGED = "FooService:changed"
}

class FooService {

    private static _data : any;
    private static _observer : Observer<FooEvent> = new Observer<FooEvent>("FooService");

    public static getData () : any {
        return this._data;
    }

    public static on (name : FooEvent, callback: ObserverCallback<FooEvent>) : ObserverDestructor {
        return this._observer.listenEvent(name, callback);
    }

    public static refreshData () {
        HttpService.doSomething().then((response) => {
            this._data = response.data;
            this._observer.triggerEvent(FooEvent.CHANGED);
        }).catch(err => {
            console.error('Error: ', err);
        });
    }

}

FooService.on(FooEvent.CHANGED, () => {

    const currentData = FooService.getData();
    // ...

});

FooService.refreshData();