Don't create your own Map class/global in javascript

In my Domain of the Ancients javascript game I have a class (which, of course, is therefore a global variable) called Map to represent the game map. As it turns out that's a bad idea! There's a perfectly good global object in javascript already called Map and so, of course, my definition ended up replacing that one. As it happens I don't use that object (at least not at the time of writing), but node.js does and it will break¹². As my unit tests in my build process use node.js for my unit testing my unit tests broke³. Anyway, to cut the story short, I've renamed my Map class to GameMap.