Mac: Typing on just about every device that isn't an actual keyboard kind of sucks, but Typeeto is a simple little Mac app that allows you to easily connect your Mac's keyboard to just about any device that uses Bluetooth.
Typeeto essentially turns your Mac's keyboard into a Bluetooth keyboard, then the app makes it dead simple to switch between devices. If you're already using a Bluetooth keyboard, it will just make it easier to switch between devices. So, if you're typing on your computer, you can tap a keyboard shortcut, then start typing on your PS4, then tap a shortcut again to return to your computer.
As best as I can tell, you can connect an unlimited number of devices and switch between them easily, which makes it a handy little utility to have around if you ever find yourself occasionally wishing for a full-size keyboard on any of your devices, but don't want to buy a special keyboard to do so.
Typeeto ($6.49) [Mac App Store]