Good Way To Make Immutable Objects

I want to have some advice about immutable objects. I made a constructor.

function Point(x, y) {
this.x = x;
this.y = y;
}

This is a very simple one and now I want to make it immutable so that
once an object is created it cannot be modified.

I came up with 2 ways.

[1]
function Point(x, y) {
this.x = function() { return x; }
this.y = function() { return y; }
}

[2]
function Point(x, y) {
this.getX = function() { return x; }
this.getY = function() { return y; }
}

They are both immutable.
You can read x and y but cannot change them.

[1] is short and easy to use but sometimes likely to be error-prone
like
var p = new Point(2, 3);
var x = p.x; //should be p.x() instead of p.x

[2] is straight-forward but looks verbose.
I have to access the data like p.getX() .

Which way is more recommendable?
And is there a better way to make an immutable object?