The Architecture of Google Closing

The Google closure compiler reads in the JavaScript that you're given. It also reads in a set of, uh, X-turns files, which are also JavaScript. And it converts all of those into an abstract Syntax Tree (AST) The AST is just a binary representation of what was in the code at the time. So when we get to the optimization stage where we're going to actually start trying to change the code, there's two different ways - one for small changes and another for big ones.