Confusion about checkProperties works on observable without subscription variable or not????

[masbhauddinsifat]

@UntilDestroy({ checkProperties: true })
@Component({})
export class HomeComponent {
  // We'll dispose it on destroy
  subscription = fromEvent(document, 'mousemove').subscribe();
}

In the example above, I understand that the subscription variable will unsubscribe automatically when the onDestroy method will call. but I want to know whether the code below works fine or not (unsubscribe automatically)????

@UntilDestroy({ checkProperties: true })
@Component({})
export class InboxComponent {
  ngOnInit() {
    interval(1000).subscribe();
  }
}

or I Should use the old syntax like below?????

@UntilDestroy()
@Component({})
export class InboxComponent {
  ngOnInit() {
    interval(1000).pipe(untilDestroyed(this)).subscribe();
  }
}

Thanks in Advance for you valueable time and helping....

[arturovt]

You should use the second example syntax, I’m guessing it’s a bit obvious that “checkProperties” option checks properties 😉 and in your example with ngOnInit there’s no property.

[masbhauddinsifat]

thank you @arturovt for clearing my confusion with your valuable response. I also thought that "checkProperties" will only work with property.

[bbarry]

I think you could do this also:

@UntilDestroy({ checkProperties: true })
@Component({})
export class InboxComponent {
  ngOnInit() {
    this.subscription = interval(1000).subscribe();
  }
}

The risk of this style is that if the ngOnInit method gets called a second time, you have a subscription hanging out somewhere in memory potentially closing over something with some mechanism to keep it alive and thus have a memory leak.

On the other hand, this syntax:

@UntilDestroy()
@Component({})
export class InboxComponent {
  ngOnInit() {
    interval(1000).pipe(untilDestroyed(this)).subscribe();
  }
}

is always safe.

[masbhauddinsifat]

thanks bro for you valuable answer