let a = 1;
let change = val => {
val = 2;
};
change(a);
console.log(a);
// ---------------------------------
let obj = { num: 1 };
let change2 = val => {
val.num = 2; // mutating the object the old reference still exists
};
change2(obj);
console.log(obj);
// ---------------------------------
let b = { num: 1 };
let c = b;
b = {}; // re-assigne the whole object chnages it's reference to a new one.
console.log(b, " ", c);
// the assignment operator changes the reference when assigning a totally new empty object.
// JS always passing by reference.
/*
Re-assigne new values to primitative or object always changes the reference,
but mutating the value will keep the refernece and not change it.
*/
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