未定义的项目推入我的数组？

Question

我创建一个对象，并推送到一个数组this.reminders，但未定义也得到推为什么是这样的？此代码会给我工作[ { description: 'Get to work in time', set_title: 'work related' }, undefined ]

var ReminderSet = function(set_name) { 
     this.set_name = set_name; 
     this.reminders = []; 
    }; 

    ReminderSet.prototype.add = function(reminder, title) { 
     this.reminders.push(reminder, title); 
     console.log(this.set_name, this.reminders) 

    }; 

    ReminderSet.prototype.list = function() { 
     console.log(this.reminders); 
    }; 

    var Reminder = function(description,set_title) { 
     this.description = description; 
     this.set_title = set_title; 
     //Describes the reminder 
    }; 

var work = new ReminderSet("work") 
      .add(new Reminder("Get to work in time", "work related")); 

Answer 1

你add()方法有两个参数：

ReminderSet.prototype.add = function(reminder, title) { /*...*/ } 

但你只能通过一个（即Reminder对象）：

var work = new ReminderSet("work") 
     .add(new Reminder("Get to work in time", "work related")); 

这导致第二个参数未定义。