How would you implement a first-in first-out queue system in javascript?

I'm trying to make a game where 6 characters (squirrels) are launched into a 2D gameplay area. They then return to the launch point where they will wait to be launched again by the player in the order that they returned in. After looking in to it, I've seen posts about a queue or first-in first-out (FIFO) system, but haven't been able to find out one would implement this in javascript.

Normally, I would post my code here, but I'm not sure what is relevant. Once I get the general concept of what to do, I can give more info. I've been stuck on this issue for a very long time now so any help at all would be greatly appreciated! Thanks.