recursion e.g.

var myNumber = 1; 

function recur(n){
    console.log("call stack is " + n); 
    n++; 
    n < 10 ? recur(n) : console.log("pop");  
}

recur(myNumber); // only the passed number get's changed
console.log(myNumber);  // the var in global scope doesn't get mutated? 

parsed*