immutability_and_safety.js

function listFruits(fs) {
  fs.sort(); 
  for(var i in fs) {
    console.log(fs[i]);
  }
}
var fruits = ["Banana", "Orange", "Apple", "Mango"];
listFruits(fruits); //prints Apple Banana Mango Orange each on their own line
console.log(fruits); //["Apple", "Banana", "Mango", "Orange"] ouch!!