If the device you want to power uses a rectifier to change the AC into DC (A power brick), it's extremely unlikely that you'll have any issues. That means your laptop is going to be fine.
The full list of electronics that work just fine with a modified sine wave is far too long to get into here. Suffice it to say that if it doesn't use an AC motor and isn't a delicate piece of medical equipment, you will be in the clear.