Question

Which of these two bits executes (counts) faster?

var i = 0;
while(true){
    i++;
}

or

var i = 0;
inc = function(){
    i++;
    inc();
}

Does the preferred way change if the looped code / function gets longer?

Answer 1

This will only give you a stack overflow as there is no end condition for the recursion :

var i = 0;
inc = function(){
    i++;
    inc();
}

For a great enough i, this will fail faster than a standard loop would do.

More generally, there is greater overhead in calling a function than just looping. Make a function when it helps your code being reusable, or readable. A loop is fast.