This AddOn allows you to show/hide Bartender bars based on whether or not you have particular auras (buffs/debuffs) active.
Each bar can be controlled by one aura (or no aura) and can be configured to either show when the aura is active or show when it's not.
You can use /bt4bh, /bt4buffhider or /bartender4buffhider in-game to bring up the options window. In this window you can configure the aura name and invert status for each bar.
To quickly fill out the aura name you can either drag a spell into the editbox or shift-click a spell link or spell book icon with the editbox focused. This assumes that the aura name is the same as the spell name, which is usually the case.
It's not possible for this AddOn (or any other) to show or hide Bartender bars based on auras while in combat. This is an intentional limitation put in place by Blizzard.
This AddOn is currently only available in English, but should work in any language provided you use the right aura names for your game locale.
If you want this AddOn available in your language and are willing to translate it, let me know and I'll set up the localisation system.
Alpha Versions and Source Code
For the latest alpha versions, check CurseForge.
The source code is available on GitHub.