JS继承四

/**
 * @param {String} className
 * @param {String/Function} superClass
 * @param {Function} classImp
 */
function  $class(className, superClass, classImp){
    if (superClass === "" ) superClass = Object;
    var  clazz = function (){
        return  function (){
            if ( typeof  this .init == "function" ){
                this .init.apply( this , arguments);
            }
        };
    }();
    var  p = clazz.prototype = new  superClass();
    var  _super = superClass.prototype;
    window[className] = clazz;
    classImp.apply(p, [_super]);
}

定义父类Person

/**
 * 父类 Person
 */
$class( 'Person' , '' , function (){
    this .init = function (name){
        this .name = name;
    };
    this .getName = function (){
        return  this .name;
    };
    this .setName = function (name){
        this .name = name;
    }
});

子类Man

/**
 * 子类 Man
 */
$class( 'Man' , Person, function (supr){
    this .init = function (name, age){
        supr.init.apply( this ,[name]); // 该句很重要
        this .age = age;
    };
    this .getAge = function (){
        return  this .age;
    };
    this .setAge = function (age){
        this .age = age;
    };
});
var  m = new  Man( 'Jack' ,25);
console.log(m.name); // Jack
console.log(m.age); // 25

从输出看可以看到子类Man的确继承了父类的属性和方法。