每日一库：JS.Class
介绍:https://github.com/RubyLouvre/JS.Class
<!doctype html>
<html>
<head>
<meta charset="gb2312" />
<title>测试</title>
<script>
var JS = {
VERSION: '2.2.1'
};
JS.Class = function(classDefinition) {
//返回目标类的真正构造器
function getClassBase() {
return function() {
//它在里面执行用户传入的构造器construct
//preventJSBaseConstructorCall是为了防止在createClassDefinition辅助方法中执行父类的construct
if (typeof this['construct'] === 'function' && preventJSBaseConstructorCall === false) {
this.construct.apply(this, arguments); //this 实例
}
};
}
//为目标类添加类成员与原型成员
function createClassDefinition(classDefinition) {
//此对象用于保存父类的同名方法
var parent = this.prototype["parent"] || (this.prototype["parent"] = {});
for (var prop in classDefinition) {
if (prop === 'statics') {
for (var sprop in classDefinition.statics) {
this[sprop] = classDefinition.statics[sprop];
}
} else {
//为目标类添加原型成员，如果是函数，那么检测它还没有同名的超类方法，如果有
if (typeof this.prototype[prop] === 'function') {
var parentMethod = this.prototype[prop];
parent[prop] = parentMethod;
}
this.prototype[prop] = classDefinition[prop];
}
}
}
var preventJSBaseConstructorCall = true;
var Base = getClassBase();
preventJSBaseConstructorCall = false;
createClassDefinition.call(Base, classDefinition);
//用于创建当前类的子类
Base.extend = function(classDefinition) {
preventJSBaseConstructorCall = true;
var SonClass = getClassBase();
SonClass.prototype = new this();//将一个父类的实例当作子类的原型
preventJSBaseConstructorCall = false;
createClassDefinition.call(SonClass, classDefinition);
SonClass.extend = this.extend;
return SonClass;
};
return Base;
};
var Animal = JS.Class({
construct: function(name) {
this.name = name;
},
shout: function(s) {
console.log(s);
}
});
//var animal = new Animal();
//animal.shout('animal'); // animal
var Dog = Animal.extend({
construct: function(name, age) {
//调用父类构造器
this.parent.construct.apply(this, arguments);
this.age = age;
},
run: function(s) {
console.log(s);
}
});
var dog = new Dog("dog", 4);
console.log(dog.name);
dog.shout("dog"); // dog
dog.run("run"); // run
console.log(dog.constructor + "")
var Shepherd = Dog.extend({
statics: {//静态成员
TYPE: "Shepherd"
},
run: function() {//方法链,调用超类同名方法
this.parent.run.call(this, "fast");
}
});
console.log(Shepherd.TYPE);//Shepherd
var shepherd = new Shepherd("shepherd", 5);
shepherd.run();//fast
var a = new Animal("xx");
console.log(a.run);
</script>
</head>
<body>
</body>
</html>
