Undefined, that's hoisting. I think it is dirty, but the point of the var statement (and your hoisting example) is that you implicitly imply the variable scope

Undefined, that's hoisting. I think it is dirty, but the point of the var statement (and your hoisting example) is that you implicitly imply the variable scope. In Coffeescript, you just do an assignment and it will be function scope if it (the variable) doesn't exist in any parent scopes? That seems dirtier to me and dangerous. If you are awesome and namespacing and keeping clean/modular/maintainable code, Coffeescript may work great.