A one-line JavaScript string formatter

Once again, I find myself on a quest to write a piece of code that's been repeated since time immemorial. This time, I want to solve the timeless problem of taking a string with some formatting markers and filling it with some data. This should have been a no-brainer, but I think I have come up with a novelty, which I want to share with you. I believe this is very simple stuff. However, I haven't…