Angular - Auto-unsubscribe

One of the nice underused features of Angular is the support for decorators (through Typescript).

From the Typescript documentation:

A Decorator is a special kind of declaration that can be attached to a class declaration, method, accessor, property, or parameter. Decorators use the form @expression, where expression must evaluate to a function that will be called at runtime with information about the decorated declaration. 

A nice example of the usage of decorators is the ngx-auto-unsubscribe library.  This Class decorator that will automatically unsubscribe from observable subscriptions when the component is destroyed.

An example:

	import { AutoUnsubscribe } from "ngx-auto-unsubscribe";
	@AutoUnsubscribe()
	@Component({
	selector: 'inbox'
	})
	export class InboxComponent {
	one: Subscription;
	two: Subscription;
	constructor( private store: Store<any>, private element : ElementRef ) {}
	ngOnInit() {
	this.one = store.select("data").subscribe(data => // do something);
	this.two = Observable.interval.subscribe(data => // do something);
	}
	// This method must be present, even if empty.
	ngOnDestroy() {
	// We'll throw an error if it doesn't
	}
	}

view raw AutoUnsubscribe.ts hosted with ❤ by GitHub