我使用的是淘汰赛与映射插件，这样我可以写code是这样的：

I'm using knockout with the mapping plugin so that I can write code like this:

function ContactViewModel() {
    //other properties...
    this.emails = ko.observableArray();
}

function ContactEmailViewModel() {
    //other properties...
    this.address = ko.observable();
}

var koContactMap = {
    'emails': {
        create: function (options) {
                    return new ContactEmailViewModel(options.data);
        }
    }
};

var model = new ContactViewModel();
ko.mapping.fromJS([JSON data from web service], koContactMap, model);

在英国，我有联系人和电子邮件和联系人具有电子邮件。

In English, I have contacts and emails, and a contact has emails.

这完美的作品，我可以加载了接触，并在数据和电子邮件填充和电子邮件的类型为 ContactEmailViewModel ，因为我想要的。

This works perfectly, and I can load the contact and have the data and emails populated, and the emails are of type ContactEmailViewModel, as I want.

但我感到困惑的是：为什么在地图创建方法返回一个奇电子邮件对象，而不是邮件对象的集。该电子邮件属性是一个集合，但似乎是由填充返回一个对象，并多次调用，一次为每个成员。

But the thing I'm confused about is: why does the map create method return a singular email object instead of a collection of email objects. The emails property is a collection, but seems to be populated by returning a single object, and is called multiple times, once for each member.

这正确填充电子邮件属性。但现在我想改变电子邮件从数组的 EmailsList 对象，这样我就可以给它的方法，和我看不出如何做到这一点，因为创建方法返回单个电子邮件，而不是整个邮件属性。

This correctly populates the emails property. But now I want to change emails from an array to an EmailsList object, so that I can give it methods, and I can't see how to do this, since the create method returns individual emails, not the whole emails property.

推荐答案

对于这种行为，你可以添加忽略上的邮件属性格式，让映射插件serperate映射电子邮件为你喂EmailsList构造带STANDAR阵列。

For that behaviour you can add ignore on the emails propery and let the mapping plugin serperate map the emails into a standar array that you feed the EmailsList constructor with.

var emailMapping = {
   create: function(opt) {
      return new Email(opt.data);
   }
};

this.emails = new EmailList(ko.mapping.fromJS(arr, emailMapping));

嗯，你也可以扩展的自定义类与observableArray我认为（还没有测试），那么ko.mapping将只需添加电子邮件到您的emailList像

Hmm, you could also extend a custom class with a observableArray I think (havent tested) that ko.mapping will then just add emails to your EmailList like

this.emails = new EmailList(); //This is is a ko.observableArray the mapping plugin will populate it with emails
ko.mapping.fromJS(data, mappingInfo, this);

的https://github.com/knockout/knockout/blob/master/src/subscribables/observableArray.js

更新：我刚刚确认了解决方案二的工作，所以我会说这就是做一个好办法

update: I just confirmed that solution two worked, so I would say thats a good way of doing it

http://jsfiddle.net/xop2go2z/

//stolen from ko source
function setPrototypeOf(obj, proto) {
        obj.__proto__ = proto;
        return obj;
    }

ko.MyList = function(arr) {
    var result = ko.observableArray(arr);
    return setPrototypeOf(result, ko.MyList.fn);
}

ko.MyList.fn = {
    pushMyThingy: function(obj) {
        this.push(obj);
    }
};