javascript - 主干和原型(prototype)初始化

Question

我有一个代码:

Application = function() {
    Application.prototype.currentQuote.collection.fetch();
};

Application.prototype = {}

Application.prototype.currentQuote = {};
Application.prototype.currentQuote.model = new (Backbone.Model.extend({
    defaults: {
        products: []
    }
}))();

Application.prototype.currentQuote.collection = new (Backbone.Collection.extend({
    model: Application.prototype.currentQuote.model,
    url: 'test.json'
}))();

App = new Application();

但是，当获取集合时，我收到“Uncaught TypeError:对象不是函数”错误。我不明白为什么，我能解决什么问题？

您可以在此处查看测试用例:https://dl.dropbox.com/u/15806777/development/bb/index.html

谢谢!

Answer 1

我猜你的问题就在这里:

Application.prototype.currentQuote.collection = new (Backbone.Collection.extend({
    model: Application.prototype.currentQuote.model, // <------------------------
    url: 'test.json'
}))();

一个collection's model是:

the model class that the collection contains.

因此 model 应该来自 Backbone.Model.extend({...}) (即“类”)，而不是来自new (Backbone.Model.extend({...})) (即模型实例)。当您要求集合创建一些模型(通过构造函数调用、fetch、add...)时，集合需要可以使用new 的东西 开启，您无法新 model_instance 因为 new operator needs a constructor function :

The new operator creates an instance of a user-defined object type or of one of the built-in object types that has a constructor function.

这就是“Uncaught TypeError:对象不是函数”错误的来源。

你需要这样的东西:

Application.prototype.currentQuote.Model = Backbone.Model.extend({
    defaults: {
        products: []
    }
});
//...
Application.prototype.currentQuote.collection = new (Backbone.Collection.extend({
    model: Application.prototype.currentQuote.Model,
    url: 'test.json'
}))();