Question

我试图扩展骨干集合，第一种方式我在声明中做了新的事情，在第二种方法中我首先声明然后我创建了一个新实例。做第一个错误，有什么区别？

var AppointmentList = new Backbone.Collection.extend({
  model: Appointment
});

和

var AppointmentList = Backbone.Collection.extend({
  model: Appointment
});

var aptlist = new AppointmentList();

Answer 1

第一个将破解

var Appointment = Backbone.Model.extend({
    defaults: {
        "time": "0000",
        "note": "This is an appointment"
    }
});


var AppointmentList = new Backbone.Collection.extend({

    model: Appointment

});

var aptlist = new AppointmentList();

在Backbone.js中我们有

  var extend = function(protoProps, staticProps) {

    var parent = this;
    var child;


    if (protoProps && _.has(protoProps, 'constructor')) {
      child = protoProps.constructor;
    } else {
      child = function(){ return parent.apply(this, arguments); };
    }

    _.extend(child, parent, staticProps);


    var Surrogate = function(){ this.constructor = child; };

    Surrogate.prototype = parent.prototype;

    child.prototype = new Surrogate;


    if (protoProps) _.extend(child.prototype, protoProps);


    child.__super__ = parent.prototype;

    return child;

  };

如果使用new运算符实例化Backbone.Collection.extend，则var parent = this将引用extend对象，但如果不使用new，则{{1 }}将引用var parent = this，因为您只能在函数上调用Backbone.Collection，代码将在此处中断：

.apply

child = function(){ return parent.apply(this, arguments); };将是一个对象。 parent是一个函数

定义新的骨干集合

1 个答案: