How to implement private attributes in JavaScript (2)_javascript skills

In the previous article, I wrote a tool function $class, and this article will improve it as follows. Implement the following functions

1, inheritance

2. When a subclass inherits a parent class, it does not inherit the private attributes of the parent class

Copy the code The code is as follows:

/**
 * @param {String} className
 * @param {String/Function} superCls
 * @param {Function} classImp
 */
function $class(className, superCls, classImp){
if(superCls === '') superCls = Object;
function clazz (){
                                                                                   = new superCls();
var _super = superCls.prototype;
window[className] = clazz;
classImp.apply(p, [_super]);
}


Write a parent class first

Copy the code

The code is as follows:/** * Parent class Person

*/

$class('Person','',function(){
// Private property age
var age;
this.init = function(n, a){
                                                                                                                  return this.name;
};
this.setName = function(name){
this.name = name;
}
this.getAge = function(){
return age;
};
this.setAge = function(a){
age = a;
};
});


Write a subclass, Inherited from Person




Copy code


The code is as follows:

$class("Man",Person, function(supr){

var school; this.init = function(n, a, s){ supr.init.apply(this, [n,a]); school = s; } this.getSchool = function(){ return school;

};

this.setSchool = function(s){
school = s;
};
});


new a subclass instance




Copy code


The code is as follows :

var m = new Man('tom', 25, 'pku');

console.log(m.name); // tom can inherit the common attribute name of the parent class Directly use the dot operator to obtain console.log(m.age); // undefined The private attribute age of the parent class cannot be directly used to obtain console.log(m.getAge()); // 25 The private attribute age can be obtained through the parent class’s public method getAge console.log(m.school); // undefined Man’s own private attribute still cannot be obtained through the dot operator console.log(m.getSchool) ()); // pku obtains the private attribute school

through the getSchool() method