How to disable swap file?

[winnie]

I have successfully created SWAP partition, ad StemOS automatically enables it on boot, so I don't need swap file no more, but it keeps auto creating and enabling it.

[Ludensius]

Late answer but maybe still useful.
You normally can't deactivate this behavior without changing the files which are on the read-only steamos partition. And next update will override this again.
But with this dirty trick you can still do it:

sudo swapoff /home/swapfile
sudo rm /home/swapfile
sudo touch /home/swapfile

This will stop the swapfile. Do this when system is idle or it will take some time.
Then delete the swapfile and create a empty file.

During boot systemd will check for the existence of the swapfile and creates a 1G file if it does not exist. With the empty file none is created. But the empty file can't be used for swap.

BTW: is you use a swap partition, for what ever reason it is automatically used during next boot without change in /etc/fstab. This a non standard behavior. Seems to be a feature of systemd to auto mount swap partitions if they are not marked as "Do not mount"