Why can't I set this variable in an object with an object with javascript?

Question

Why cant I do this I do not understand?

function hello() {
    this.say = 'fdfsd';
}
function goodbye() {
    this.example = new hello();
}

But it works if I do;

function hello() {
    this.say = 'fdfsd';
}
function goodbye() {
    this.example = false;
}
var goodbye = new goodbye();
goodbye.example = new hello();

Answer 1

You have to construct goodbye

var x = new goodbye();

Invoking the constructor will create a new object (of type goodbye ).

This line will construct an object of type hello and assign it to the example attribute of the goodbye instance

this.example = new hello();

After construction this is what the instance of goodbye will contain

// x
{
    example: {
        say: "fdfsd"
    }
}