获取并添加模型到集合

Question

var RippleId = Backbone.Model.extend({ 
    initialize: function(toresolve) { 
     this.url= config.rippleaccount.id.urlModel+toresolve; 
     this.set('id', toresolve) 
    } 
}); 

var RippleIds = Backbone.Collection.extend({ 
    model: RippleId, 

    createIdList: function(toresolves) { 
     var self = this; 
     _.each(toresolves, function(toresolve) { 

      var model = new RippleId(toresolve); 
      model.fetch({ 
       success: function(model,response) { 
        self.add(model); 
       } 
      }); 

     }); 
    } 
}); 

var toresolvelist = new rippleids();  
toresolvelist.createIdList(toresolves); 

toresolvelist.toJSON()不会返回任何内容（而不是集合的对象）。

我想这是一个等待收集已正确填充的问题，但我认为这是好的，因为我在添加模型之前等待模型获取成功。

当我console.log(toresolvelist)它告诉我，结果在这里。但我无法通过.get或toJSON访问它，所以我猜console.log正在欺骗我。

我很难确定问题是什么，我无法解决它。

非常感谢！

Answer 1

要获得模型的完整列表，您需要等待每个XHR呼叫解决。这可以jquery.when上返回的值来完成通过model.fetch：

var RippleIds = Backbone.Collection.extend({ 
    model: RippleId, 

    createIdList: function(toresolves) { 
     var self = this, xhrs = []; 

     xhrs = _.map(toresolves, function(toresolve) { 
      var model = new RippleId(toresolve); 
      var xhr = model.fetch().then(function() { 
       self.add(model); 
      }); 
      return xhr; 
     }); 

     // promise that will resolve when all fetches have completed 
     var combined = $.when.apply(null, xhrs); 

     // event triggered when all models have been instantiated 
     combined.then(function() { 
      self.trigger('allin'); 
     }); 

     return combined; 
    } 
}); 

var toresolvelist = new rippleids();  
var promise = toresolvelist.createIdList(toresolves); 

// with an event 
toresolvelist.on('allin', function() { 
    console.log('get model with an event', toresolvelist.get(1)); 
}); 

// with a promise 
promise.then(function() { 
    console.log(toresolvelist.toJSON()); 
}); 

并演示http://jsfiddle.net/nikoshr/13mz3r3y/4/