backbone.js - Backbone.Collection#where 上的 toJSON？

Question

我不知道为什么，但我不能让它工作。

var friends = new Backbone.Collection([
  {name: "Athos",      job: "Musketeer"},
  {name: "Porthos",    job: "Musketeer"},
  {name: "Aramis",     job: "Musketeer"},
  {name: "d'Artagnan", job: "Guard"},
]);

friends.where({job: "Musketeer"}).toJSON()

我收到 Uncaught TypeError: Object [object Object] has no method 'toJSON' .

我做错了什么，如何将过滤后的集合转换为 JSON？

Answer 1

什么Underscore.where方法返回的是 Array不是 Backbone.Collection所以它没有 toJSON方法定义。

所以你可以做两件事:

迭代元素并映射结果:

var result = friends.where({job: "Musketeer"});
_.map( result, function( model ){ return model.toJSON(); } );

jsFiddle code

实现一个返回正确 Backbone.Collection 的 Collection searcher 方法:

var Friends = Backbone.Collection.extend({
    search: function( opts ){
        var result = this.where( opts );
        var resultCollection = new Friends( result );

        return resultCollection;
    }
});

var myFriends = new Friends([
  {name: "Athos",      job: "Musketeer"},
  {name: "Porthos",    job: "Musketeer"},
  {name: "Aramis",     job: "Musketeer"},
  {name: "d'Artagnan", job: "Guard"},
]);

myFriends.search({ job: "Musketeer" }).toJSON();​

jsFiddle code