It's been said a few times in the comments, but it really deserves its own answer: When a new thing comes up for you, just search for it on Urban Dictionary.
There's no need to spend weeks or months immersing yourself in TikTok, Instagram, or massively multiplayer video games. Just look it up on that site and in a few seconds, you'll know, and can move on with your work.
Commentators point out, correctly, that Urban Dictionary is frequently profane, sometimes ambiguous, and even blocked at certain workplaces (in which case: use your phone or home computer). Nonetheless, I find it to be the quickest way to get an on-target answer for my purposes. Other options include:
- StayHipp
- Slang.org
- Know Your Meme
- Google "what does X mean"
As a test case: Urban Dictionary immediately gives a valid definition to both the OP's questions on "based" and "/ff", whereas none of the other options here do.