Backbone.js模型，指定属性

Question

我想知道是否有办法指定必须在实例化时初始化的模型属性。

Book = Backbone.Model.extent({
 title: "title",
 author: "author",
 year: "year"

});

每当我实例化模型时，我希望限制这几个属性必须初始化，或者至少足以限制不能设置新属性：

var book = new Book({
  title: "something",
  pages: "350"
});

Answer 1

试试这个：

Book = Backbone.Model.extent({
    defaults: {
     title: "title",
     author: "author",
     year: "year"
    }
});

---

如果要约束这些属性，可以使用validate方法：

Book = Backbone.Model.extent({
    defaults: {
     title: "title",
     author: "author",
     year: "year"
    },

    validate: function(attrs, options) {
        var isValid = true;
        _.each(_.keys(attrs), function(key) {
            if (!this.defaults[key]) {
                isValid = false;
            }
        }, this);
        return isValid;
    }
});

Answer 2

尝试

---

Book = Backbone.Model.extend({ 
defaults: {
     title: "title",
     author: "author",
     year: "year"
    }
});