Question

我有一个人员类，该人员类具有User和Admin的子类，User将创建用户实例... 现在，通过检查arguments.length来验证我的addPerson（）属性无效。

即使我可以记录arguments.length

，if语句也不会执行

var Person = function(name, email) {
  this.name = name;
  this.email = email;

  this.addPerson = function(name, email) {
    var paraLength = arguments.length;
    console.log(paraLength) //logs 2
    if(paraLength < 2 || > 2) {
      return "Input must be just name and email"; //does nothing
    }else{
    //do other things
    }
}

const User = function(name, email) {
  Person.call(this, name, email);
  this.addPerson(name, email); //adding user on execution
};

User.prototype = Object.create(Person.prototype);

//Pointing User constructor to itself so it can override properties
User.prototype.constructor = User;
var user1 = new User("user1", "email@gmail", "this error", "not just ignored")

如果传入的参数小于或大于两个，我想在return语句上终止。注意：我打算使用对象原型

Answer 1

您有一些语法错误-在您的def print_values(self, reverse=False): values = [val for val in self.__list_generator()] if values: print("Linked list: " + str(values)) else: print("Linked List is currently empty.") def __list_generator(self): ''' A Generator remembers its state. When `yield` is hit it will return like a `return` statement would however the next time the method is called it will start at the yield statment instead of starting at the beginning of the method. ''' cur_node = self.head_node while cur_node != None: yield cur_node.node_value # return the current node value # Next time this method is called # Go to the next node cur_node = cur_node.nextNode语句中，第二个比较项中缺少def print_values(self, reverse=False): cur_node = self.head_node if cur_node: print('Linked list: ', end='') while cur_node: print("'{}' ".format(cur_node.node_value), end='') cur_node = cur_node.nextNode else: print("Linked List is currently empty.")（应为if）。您还没有关闭原始的paraLength函数。并且由于您没有使用|| paraLength > 2的{{1}}值执行任何操作，因此没有任何反应-使用Person将和日志返回到控制台：

return

Answer 2

不确定User.addPerson()应该做什么，而是回答您的主要问题…

如果您想捕获在new User()函数中传递给addPerson()的参数太多（或太少），则可以传递arguments而不只是名称和电子邮件。您可以执行以下操作：

this.addPerson.apply(this, arguments);

使addPerson看到传递给User()的所有参数

var Person = function(name, email) {
  this.name = name;
  this.email = email;

  this.addPerson = function(name, email) {
    var paraLength = arguments.length;
    console.log(paraLength) //logs 2
    if(paraLength < 2 || paraLength > 2) {
      console.log( "Input must be just name and email"); //does nothing
    }else{
    //do other things
    }
}
}

const User = function(name, email) {
  Person.call(this, name, email);
  this.addPerson.apply(this, arguments); //adding user on execution
};

User.prototype = Object.create(Person.prototype);

var user1 = new User("user1", "email@gmail", "this error", "not just ignored")

在对象原型中使用arguments.length

2 个答案: