I recall a version that was more complicated:
indexOf(toStr(qualityOf({tag})), 'Bad_NotFound') = -1 &&
indexOf(toStr(qualityOf({tag})), 'Bad_Disabled') = -1
But, as of around 8.1.10:
This simplified version makes everything a tad more manageable:
qualityOf({tag}) != 'Bad_NotFound' &&
qualityOf({tag}) != 'Bad_Disabled'
I am using the above in several views (Edge projects). While it does feel a bit use-case-specific to port over the isAvailable function…I’d certainly use it as well. To echo your use, I would be pointing the function at an existing property (which is bound to a tag) as well.