Family = function(name) {
this._Name = name;
}
Family.prototype = {
getName: function() {
return this._Name;
},People: function(num) {
this._Number = num;
}
}
Family.People.prototype = {
clearNumber: function() {
this._Number = 0;
}
}
人是一个嵌套的类.它的父类是Family.
解决方法
工作代码
// function doesn't need "new" operator
var Family = function(name) { this._Name = name; };
Family.prototype = {
getName: function() { return this._Name; },// missing comma
People: function(num) {
this._Number = num;
}
};
// work with prototypes
Family.prototype.People.prototype = {
clearNumber: function() { this._Number = 0; }
};
这会奏效.但你必须要知道,当你打电话时：
var f = new Family("Doe");
f.People只是一个对象构造函数,而不是其他对象的实例.你必须实例化它,如：
f.members = new f.People(3);
你在你的实例中有一个相当混乱的构造函数.
更好的方法
因此,如果您以这种方式编写原型可能会更好：
var Family = function(name) {
this._Name = name;
this.getName = function() { return this._Name; };
};
Family.People = function(num) {
this._Number = num;
this.clearNumber = function() { this._Number = 0; };
};
这实际上是一个类(而不是实例)中的类.所以上线将以这种方式调用：
var f = new Family("Doe");
f.members = new Family.People(3);
向下钻取f实例看起来像：
f
_Name
getName()
members
_Number
clearNumber()
私有变量
var Family = function(name) {
var _name = name;
this.getName = function() { return _name; };
};
Family.People = function(num) {
var _num = num;
this.getNumber = function() { return _num; }
this.clearNumber = function() { _num = 0; };
};
通过这种方式,我们将变量设为私有且只能在其中访问,因此无法在外部进行操作.您必须始终使用函数来操作它们.这使得它更加健壮,尤其是当存在与变量值相关的某些业务规则时.
var f = new Family("Doe");
f._name; // this is undefined because "_name" is private closure variable
现在,向下钻取f实例看起来更像是一个类对象实例：
f
getName()
members
getNumber()
clearNumber()
