js工廠模式的無法識別對象類型與構(gòu)造函數(shù)在哪體現(xiàn)？

1）創(chuàng)建對象的過程中并沒有體現(xiàn)出工廠模式。
2）可以了解下js通過構(gòu)造函數(shù)創(chuàng)建對象的過程，應(yīng)該就能解釋 console.log(A1 instanceof A); //不是A的實例嗎？

var A1 = new A('qwe', 18)這句：

1. "new" will create an empty object first, and assign property through this.
2. If there is no return or an primitive return inside the function, it will return the new created object to A. But if there is a non-primitive returning inner the function, like an object, array, or function , it will return the non-primitive to A.

function A(name,age) {
    var o = new Object()
    o.name = name
    o.age = age
    o.sayName = function () {
        alert(this.name)
    }
    return 1;
}
var A1 = new A('qwe',18); // A1 is a instance of A.

function A(name,age) {
    var o = new Object()
    o.name = name
    o.age = age
    o.sayName = function () {
        alert(this.name)
    }
    return {};
}
var A1 = new A('qwe',18); // A1 is a instance of object.

function A(name,age) {
    var o = new Object()
    o.name = name
    o.age = age
    o.sayName = function () {
        alert(this.name)
    }
    return null;
}
var A1 = new A('qwe',18)
A1 instanceof A ?   
和工廠模式關(guān)系在哪里？