How to unsubscribe?

Question

JavaScript

There is a function like this

const sub: Subscription = this.usersService.allUsers
 .subscribe(users=> {
otherBehaviorSubject.next(users.filter(/*some filter function*/));
sub.unsubscribe(); // В этом моменте постоянно матерится на то что sub === undefined
});

I only need to get a non-value from the BehaviorSubject once and immediately unsubscribe, how can I do this?

Answer 1

Coder321 at least sub.unsubscribe(); put out of brackets

const sub: Subscription = this.usersService.allUsers
 .subscribe(users=> {
otherBehaviorSubject.next(users.filter(/*some filter function*/));
});
sub.unsubscribe();

Answer 2

Use the operator takeit selects N elements from the sequence, completes it and unsubscribes

this.usersService.allUsers
 .take(1)
 .subscribe(users=> {
    otherBehaviorSubject.next(users.filter(/*some filter function*/));
 });