Javascript 如何处理嵌套在RelationalModel中的集合？

我用于创建复杂的模型层次结构，代码如下所示：

var ModelA = Backbone.Model.extend({
    initialize: function () {
        console.log('model a initialized!')
    }
});

var CollectionA = Backbone.Collection.extend({
    model: ModelA
});

var ModelB = Backbone.RelationalModel.extend({
    relations: [{
        type: Backbone.HasMany,
        key: 'Collection',
        collectionType: CollectionA
    }]
});

var data = new ModelB({
    name: 'ModelB',
    Collection: [{
        name: 'ModelA-1'
    }, {
        name: 'ModelA-2'
    }]
});

console.log(data.get('Collection').at(0) instanceof ModelA); // false
console.log(data.get('Collection').at(0) instanceof ModelB); // true
console.log(JSON.stringify(data.toJSON())); 
// {"name":"ModelB","Collection":[{"name":"ModelA-1","Collection":[]},{"name":"ModelA-2","Collection":[]}]}

var ModelA = Backbone.RelationalModel.extend({
    initialize: function () {
        console.log('model a initialized!')
    }
});
...

var ModelB = Backbone.RelationalModel.extend({
    relations: [{
        type: Backbone.HasMany,
        relatedModel: 'ModelA',
        key: 'Collection',
        collectionType: CollectionA
    }]
});

---

如您所见，即使成功创建了ModelB，也不会调用ModelA的initialize。检查类型可以证明集合中的对象不是ModelA。如何修复此问题？

需要两个更改：使ModelA成为RelationalModel，而不仅仅是标准模型，并告诉ModelB ModelA是其RelationalModel，如下所示：

var ModelA = Backbone.Model.extend({
    initialize: function () {
        console.log('model a initialized!')
    }
});

var CollectionA = Backbone.Collection.extend({
    model: ModelA
});

var ModelB = Backbone.RelationalModel.extend({
    relations: [{
        type: Backbone.HasMany,
        key: 'Collection',
        collectionType: CollectionA
    }]
});

var data = new ModelB({
    name: 'ModelB',
    Collection: [{
        name: 'ModelA-1'
    }, {
        name: 'ModelA-2'
    }]
});

console.log(data.get('Collection').at(0) instanceof ModelA); // false
console.log(data.get('Collection').at(0) instanceof ModelB); // true
console.log(JSON.stringify(data.toJSON())); 
// {"name":"ModelB","Collection":[{"name":"ModelA-1","Collection":[]},{"name":"ModelA-2","Collection":[]}]}

var ModelA = Backbone.RelationalModel.extend({
    initialize: function () {
        console.log('model a initialized!')
    }
});
...

var ModelB = Backbone.RelationalModel.extend({
    relations: [{
        type: Backbone.HasMany,
        relatedModel: 'ModelA',
        key: 'Collection',
        collectionType: CollectionA
    }]
});