Enhancing Subscription Collection with Angular and RX Framework

Question

Enhancing Subscription Collection with Angular and RX Framework

Exciting Update!

After successfully finding the solution, I created a handy ng2-rx-collector tool inspired by the accepted answer to simplify the process even further. It's designed to assist anyone who might encounter similar challenges in the future.

The Initial Question

Imagine having a component with two subscriptions to hot observables. These subscriptions are set up in ngOnInit and unsubscribed in ngOnDestroy to prevent memory leaks or unexpected behavior:

public ngOnInit() {
  this.s1 = o1.subscribe(console.debug.bind(console));
  this.s2 = o2.subscribe(console.debug.bind(console));
}

public ngOnDestroy() {
  this.s1.unsubscribe();
  this.s2.unsubscribe();
}

Although I appreciate Rx, I find the process of managing subscriptions overwhelming:

Creating a private subscription property for each subscription
Assigning the property to a subscription (which looks messy due to the logic placement)
Unsubscribing from each subscription on destroy

Is there a better way to handle this?

For example, in RxSwift, they utilize a DisposeBag to streamline the process. In TypeScript, this concept could be translated as:

private let bag = DisposeBag();

...

o1.subscribe(...).addDisposableTo(bag);

This would involve only one disposal process. However, I have been unable to find a similar function for Subscription.

I would greatly appreciate any thoughts or suggestions on improving this process.

angular typescript rxjs rxjs5

Answer 1

Answer №1

If you want to achieve this functionality, you can follow this approach:

const teardownSubject = new Subject<void>();

public ngOnInit() {
    observable1.pipe(takeUntil(teardownSubject)).subscribe(console.debug.bind(console));
    observable2.pipe(takeUntil(teardownSubject)).subscribe(console.debug.bind(console));
}

public ngOnDestroy() {
    teardownSubject.next();
}

Answer 2

If you want to achieve this functionality, you can follow this approach:

const teardownSubject = new Subject<void>();

public ngOnInit() {
    observable1.pipe(takeUntil(teardownSubject)).subscribe(console.debug.bind(console));
    observable2.pipe(takeUntil(teardownSubject)).subscribe(console.debug.bind(console));
}

public ngOnDestroy() {
    teardownSubject.next();
}

Answer 3

Answer №2

In the past, this concept was known as "disposables" in RxJS 4 or in RxPHP. However, in RxJS 5, it is referred to as Subscription while serving the same purpose.

Here is an example where two source Observables are utilized. Both unsubscribe calls are encapsulated within a single Subscription object, which includes a callback that is executed when its unsubscribe() method is called.

var source1 = Observable.interval(250);
var source2 = Observable.interval(350);

let sub1 = source1.subscribe(val => console.log(val));
let sub2 = source2.subscribe(val => console.log(val));

let subscriptions = new Subscription(() => {
    sub1.unsubscribe();
    sub2.unsubscribe();
});

setTimeout(() => {
    subscriptions.unsubscribe();
}, 3000);

Similarly, it is possible to take the initial Subscription from source1.subscribe and add another Subscription that will also have its own unsubscribe() method, using the add() method:

var source1 = Observable.interval(250);
var source2 = Observable.interval(350);

let subscriptions = source1.subscribe(val => console.log(val));
subscriptions.add(source2.subscribe(val => console.log(val)));

setTimeout(() => {
    subscriptions.unsubscribe();
}, 3000);

For more detailed information, refer to the source code: https://github.com/ReactiveX/rxjs/blob/master/src/Subscription.ts

Answer 4

In the past, this concept was known as "disposables" in RxJS 4 or in RxPHP. However, in RxJS 5, it is referred to as Subscription while serving the same purpose.

Here is an example where two source Observables are utilized. Both unsubscribe calls are encapsulated within a single Subscription object, which includes a callback that is executed when its unsubscribe() method is called.

var source1 = Observable.interval(250);
var source2 = Observable.interval(350);

let sub1 = source1.subscribe(val => console.log(val));
let sub2 = source2.subscribe(val => console.log(val));

let subscriptions = new Subscription(() => {
    sub1.unsubscribe();
    sub2.unsubscribe();
});

setTimeout(() => {
    subscriptions.unsubscribe();
}, 3000);

Similarly, it is possible to take the initial Subscription from source1.subscribe and add another Subscription that will also have its own unsubscribe() method, using the add() method:

var source1 = Observable.interval(250);
var source2 = Observable.interval(350);

let subscriptions = source1.subscribe(val => console.log(val));
subscriptions.add(source2.subscribe(val => console.log(val)));

setTimeout(() => {
    subscriptions.unsubscribe();
}, 3000);

For more detailed information, refer to the source code: https://github.com/ReactiveX/rxjs/blob/master/src/Subscription.ts

Enhancing Subscription Collection with Angular and RX Framework

Answer №1

Answer №2

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