Observer

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

It works full stack on every JS system.

You'll use it like this:

import Observer from "./src/fi/hg/core/Observer";

enum FooEvent {
    CHANGED = "FooService:changed",
}

class FooService {
    private static _data: any;

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

    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();