如何使用'new'从另一个函数/对象中的函数创建对象

Question

I am trying to create an api that extends some functionality of Tizen.

Tizen has a way of creating objects such as: 'new tizen.ContactName(...)' and 'addressbook = tizen.contact.getDefaultAddressBook();'.

This seems to be a nice way to group together methods and objects when there are a lot of them.

So, for example I want to extend the contact handling:

(An external js-file)

function ContactManager(){ //edited by comment
    var self = this;

    this.add = function(details, posCallback, negCallback){
    //do stuff to add contact

    this.otherMethod(){...}
}

etc.

I can call this by using: var contactManager = new ContactManager(); and it works fine. Now I want to access by include it in another object(?) so that it looks like: var contactManager = new myTizen.ContactManager() .

I tried:

function myTizen(){

this.ContactManager = function(){
    //methods and stuff
    }
}

This doesn't work. Why? How should I build my "API"?

Answer 1

I see it like this

define some object myTizen

then set myTizen.ContactManager = somefunction();

Answer 2

Here's what you want:

function myTizen() {
    function whatevername() {
        // methods and stuff
    }
    // you can even extend whatevername's prototype down here

    this.ContactManager = whatevername; // please note the lack of parentheses
}

// here's another way you could do it:
function alternateMyTizen() {
}

function alternatewhatever() {
    // methods and stuff
}
// extend the prototype if you choose

alternateMyTizen.prototype.ContactManager = alternatewhatever;

The main difference between option 1 and option 2 is that in the second method, your "subclass" remains in scope and can be used independently of your myTizen class, in the first method once the constructor goes out of scope, you can only access it through myTizen.ContactManager .