在收集Backbone.js的模型 [英] Backbone.js model with collection

问题描述

我有2个型号，一个集合。 JobSummary 是一个模型， JobSummaryList 是 JobSummary 的集合项目，然后我有一个 JobSummarySnapshot 模型包含 JobSummaryList ：

I have 2 models and one collection. JobSummary is a model, JobSummaryList is a collection of JobSummary items, and then I have a JobSummarySnapshot model that contains a JobSummaryList:

JobSummary = Backbone.Model.extend({});

JobSummaryList = Backbone.Collection.extend({
    model: JobSummary
});

JobSummarySnapshot = Backbone.Model.extend({
    url: '/JobSummaryList',

    defaults: {
        pageNumber: 1,
        summaryList: new JobSummaryList()
    }
});

当我称之为读取的 JobSummarySnapshot 对象时，它得到的一切......除了当我移动通过 summaryList 收集他们都是类型的对象，而不是 JobSummary

When I call fetch on the JobSummarySnapshot object, it gets everything... Except when I move through the summaryList collection they are all of type object and not JobSummary.

我想这是有道理的，因为比默认对象，它不知道其他的 summaryList 应是类型 JobSummaryList 。我可以通过每个项目，并将其转换为 JobSummary 的对象，但我希望有办法做到这一点，而不必做手工。

I suppose this makes sense since other than the defaults object, it doesn't know that the summaryList should be of type JobSummaryList. I can go through each item and convert it to a JobSummary object, but I was hoping there was a way to do it without having to do it manually.

下面是我的测试code（工作的jsfiddle这里）：

Here's my test code (working jsfiddle here):

var returnData = {
    pageNumber: 3,
    summaryList: [
        {
        id: 5,
        name: 'name1'},
    {
        id: 6,
        name: 'name2'}
    ]
}; 

var fakeserver = sinon.fakeServer.create();
fakeserver.respondWith('GET', '/JobSummaryList', [200,
{
    'Content-Type': 'application/json'},
                                JSON.stringify(returnData)]);

var callback = sinon.spy();


var summarySnapshot = new JobSummarySnapshot();
summarySnapshot.bind('change', callback);

summarySnapshot.fetch();
fakeserver.respond();

var theReturnedList = callback.getCall(0).args[0].attributes.summaryList;

_.each(theReturnedList, function(item) {
    console.log('Original Item: ');
    console.log(item instanceof JobSummary); // IS FALSE
    var convertedItem = new JobSummary(item);
    console.log('converted item: ');
    console.log(convertedItem instanceof JobSummary); // IS TRUE
});

更新： 它发生，我认为我可以覆盖解析功能，并设置这种方式......我有现在这样：

UPDATE: It occurred to me that I could override the parse function and set it that way... I have this now:

JobSummarySnapshot = Backbone.Model.extend({
    url: '/JobSummaryList',

    defaults: {
        pageNumber: 1,
        summaryList: new JobSummaryList()
    },

    parse: function(response) {
        this.set({pageNumber: response.pageNumber});

        var summaryList = new JobSummaryList();
        summaryList.add(response.summaryList);

        this.set({summaryList: summaryList});
    }
});

这工作至今。离开的问题开放，以防有人评论它....

This works so far. Leaving the question open in case someone has comment on it....

推荐答案

您解析（）函数不应该设置（）任何事情，它是一个更好的做法，只是返回的属性，骨干将设置它​​的照顾。例如，

Your parse() function shouldn't set() anything, its a better practice to just return the attributes, Backbone will take care of setting it. e.g.

parse: function(response) {
    response.summaryList = new JobSummaryList(response.summaryList);
    return response;
}

无论你从解析（）是的传递给设置（） 。

不返回任何东西（这好像回到未定义）是一样的调用设置（不确定），其中可能导致其无法通过验证，或其他一些意想不到的结果，如果您的自定义的validate（） / 设置（）方法期望得到的对象。如果您的验证或设置（）方法因为失败，传递给<$ C $的 options.success 回调C> Backbone.Model＃取（）将不会被调用。

Not returning anything (which is like returning undefined) is the same as calling set(undefined), which could cause it not to pass validation, or some other unexpected results if your custom validate()/set() methods expects to get an object. If your validation or set() method fails because of that, the options.success callback passed to Backbone.Model#fetch() won't be called.

此外，为了使这更通用的，从而使设置（）荷兰国际集团从其他地方一个普通的对象（而不是仅仅从服务器响应），也影响它，您可能要重写设置（）来代替：

Also, to make this more generic, so that set()ing to a plain object from other places (and not only from the server response) also effects it, you might want to override set() instead:

set: function(attributes, options) {
    if (attributes.summaryList !== undefined && !(attributes.summaryList instanceof JobSummaryList)) {
        attributes.summaryList = new JobSummaryList(attributes.summaryList);
    }
    return Backbone.Model.prototype.set.call(this, attributes, options);
}

您可能还会发现骨干关系有趣的 - 这使得它更容易处理嵌套在型号的集合/模型

You might also find Backbone-relational interesting - it makes it much easier to deal with collections/models nested inside models.

修改我忘了从set（）方法返回时，code现已更新

edit I forgot to return from the set() method, the code is now updated

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