call_by_sharing.js

function changeStuff(num, obj1, obj2){
  num = num * 10; // num is the value 10; once passed to the function, it has no relation to the variable `num` outside the function
  obj1.item = “changed”;
  obj2 = {item: “changed”};
}

var num = 10;
var obj1 = {item: “unchanged”};
var obj2 = {item: “unchanged”};

changeStuff(num, obj1, obj2);

console.log(num); // 10
console.log(obj1.item); // ‘changed’
console.log(obj2.item); // ‘unchanged’