When a player jumps, high enough to get falldamage, how do i cancel the damage?

Title says all, need help

PHP:

    public function onDamage(EntityDamageEvent $event)
    {
        if ($event->getEntity() instanceof Player) {
            if ($event->getCause() === EntityDamageEvent::CAUSE_FALL) {
                 $event->setCancelled();
            }
        }
    }

I think he meant only when the player actively jumped, that it should be cancelled.
You could do it with an array where the last jump time is saved