Manually update the length after deleting item from the array

[pauliax]

AvatarItemToken.sol

    avatarItems[tokenIndex] = avatarItems[avatarItems.length.sub(1)];
    delete avatarItems[avatarItems.length.sub(1)];

Now the length of the array is not reduced, just the last element becomes empty. To fully remove an item you need to manually update the length property: avatarItems.length--;

[shaokun11]

@pauliax Thanks your opinions. At this version, I use the avatarItems.length to generate token id , if I really reduce the length, which will cause duplicate token id. so I just swap burned item position for last item position.