Comparison of module method declarations

It really does execute the code. For example:

var a = [];
for (var i=0;i<100;i++)a[i]=i;

will create a 100 element array called a after it is uploaded.

However functions (and what is in them) won't be executed (unless you explicitly execute them). So:

function foo() {
  var a = [];  
  for (var i=0;i<100;i++)a[i]=i;
  return a;
}

won't create an array. All that is stored is some data representing the function, and the source code inside it.

It might be worth taking a look at this: http://www.espruino.com/Performance