javascript - Backbone 的一个属性可以包含一个集合吗？

Question

在主干中，存储作者和书籍之间关系(在本地存储中)的理想方式是什么。

是否可以将集合作为属性，或者应该使用数组还是...？

var book = Backbone.Model.extend({ 
    defaults:{ 
        title: ''
    }
});

var books = Backbone.Collection.extend({
    model: book
});


var author = Backbone.Model.extend({
        defaults:{ 
        firstName: '',
        lastName: '', 
        books: new books()
        }
});

var authors = Backbone.Collection.extend({
    model: author,
    localStorage: new Backbone.LocalStorage("authors")
});

Answer 1

在 Backbone 中处理嵌套集合没有唯一正确的方法。引自 Backbone FAQ :

Backbone doesn't include direct support for nested models and collections or "has many" associations because there are a number of good patterns for modeling structured data on the client side, and Backbone should provide the foundation for implementing any of them.

常见问题解答还建议了一种模式并提供了指向 Extensions, Plugins, Resources 的链接页面，它链接到许多可用于处理嵌套模型和模型关系的库。

也就是说，我有时会这样处理这个问题:

var Author = Backbone.Model.extend({

  initialize: function(attrs, options) {
    //convert the child array into a collection, even if parse was not called
    var books = attrs ? attrs.books : [];
    if(!(books instanceof Books)) {
        this.set('books', new Books(books), {silent:true});
    }
  },

  //the books property does not need to be declared in the defaults
  //because the initialize method will create it if not passed
  defaults: {
    firstName: '',
    lastName: ''    
  },

  //override parse so server-sent JSON is automatically
  //parsed from books array to Books collection
  parse: function(attrs) {
    attrs.books = new Books(attrs.books);
    return attrs;
  },

  //override toJSON so the Books collection is automatically
  //converted to an array 
  toJSON: function() {
    var json = Backbone.Model.prototype.toJSON.call(this);
    if(json.books instanceof Books) {
      json.books = json.books.toJSON();
    }
    return json;
  }
});

评论有望解释它是如何工作的，但重点是您可以像往常一样使用该模型:使用集合、数组或什么都不初始化子项，从服务器获取，将它们发送到服务器，它应该透明地工作。有相当多的样板代码需要编写，但如果您发现自己在重复相同的代码，那么将其抽象为基类相对简单。

编辑 小更正，您不需要 defaults 对象中定义的 books，因为如果缺少，构造函数会创建它。

/代码示例未测试