As I understand, object references x in x = { greet: hi } stores a reference to object { greet:hi} unlike primitive types that hold actual values ( y=10)
In the following code, console.log(y) outputs {greet: "hi"}.
Why does y object reference is not updated to point to {greet: 'hello'} when x obj ref is updated to point to x = {greet: 'hello'}
var x = {greet: 'hi'};
var y = x;
x = {greet: 'hello'};
console.log(y);
console.log(x)
Because in line x = {greet: 'hello'}; a new object is being created.
Use x.greet = 'hello'; to update old object.
var x = {greet: 'hi'};
var y = x;
x.greet = 'hello';
document.getElementById("text_show").innerHTML= x.greet + " | " + y.greet;<div id="text_show"></div>JavaScript
x.greet = "hello". In this case y would look like xWhy does y object reference is not updated to point to {greet: 'hello'} when x obj ref is updated to point to x = {greet: 'hello'}
Because you have assigned a new reference to x while y is still pointing to original one.
When you say
var y = x;
you are pointing y to the same reference that x was pointing to, you are not pointing y to x.
you are not pointing y to x. exactly, x is a reference and that reference is also copied to y when I write var y = x so when that reference changes in x that change should propagate to y also. Right?
var x = {greet: 'hi'}; var y = x; x.greet = 'hello'; then y.greet would also have changed.
y = xmakesyand alias ofx, i.e. that they're both the same variable really. That's not how it works. You're merely assigning the object reference stored inxtoy.x = {greet: 'hello'};, you are replacing the reference itself. So now the variable will hold pointer to some other location and object at previous location would remain as is. If no one is referencing it, GC will get rid of it.