Isn't firstValueFrom() written incorrectly? It keeps one subscription in memory forever, every time you use it.

[Evertt]

When I see how firstValueFrom is defined here.

Then I think the line that I selected, which for reference I'll just paste here too:

source.subscribe(subscriber);

should actually be:

source.pipe(take(1)).subscribe(subscriber);

Right? Because why would firstValueFrom hold onto the subscription after the first value has passed?
Maybe piping it with a take(1) operator isn't the cleanest solution, but do you see what I'm getting at?

[demensky]

After source emits the first event, an unsubscribe occurs.

---

const example = new Observable((subscriber) => {
  const id = setInterval(() => {
    subscriber.next();
  }, 2000);

  return () => {
    console.log('TeardownLogic');
    clearInterval(id);
  };
});

The following two examples are equivalent:

const subscriber1 = new Subscriber({
  next: () => {
    console.log('subscriber next');
    subscriber1.unsubscribe();
  },
  error: noop,
  complete: noop,
});

example$.subscribe(subscriber1);

const subscriber2 = example$.subscribe({
  next: () => {
    console.log('subscriber next');
    subscriber2.unsubscribe();
  },
});