我要评论最近我们课程到了面向对象这一章节，为了让大家更好的理解面向对象：
var person = class.extend({
init: function(isdancing){
this.dancing = isdancing;
},
dance: function(){
return this.dancing;
}
});
var ninja = person.extend({
init: function(){
this._super( false );
},
dance: function(){
// call the inherited version of dance()
return this._super();
},
swingsword: function(){
return true;
}
});
var p = new person(true);
p.dance(); // => true
var n = new ninja();
n.dance(); // => false
n.swingsword(); // => true
// should all be true
p instanceof person && p instanceof class &&
n instanceof ninja && n instanceof person && n instanceof class
我认为上面的这种api设计是比较nice的，它达到了几个目的：一、所有的类继承自一个祖先class二、子类可以覆盖掉父类上的方法，当然了，可以通过super方法来调用父为的同名方法
下面是我的实现：
/* simple javascript inheritance
* by john resig https://ejohn.org/
* mit licensed.
*/
// inspired by base2 and prototype
(function(){
var initializing = false, fntest = /xyz/.test(function(){xyz;}) ? /\b_super\b/ : /.*/;
// the base class implementation (does nothing)
this.class = function(){};
// create a new class that inherits from this class
class.extend = function(prop) {
var _super = this.prototype;
// instantiate a base class (but only create the instance,
// don't run the init constructor)
initializing = true;
var prototype = new this();
initializing = false;
// copy the properties over onto the new prototype
for (var name in prop) {
// check if we're overwriting an existing function
prototype[name] = typeof prop[name] == "function" &&
typeof _super[name] == "function" && fntest.test(prop[name]) ?
(function(name, fn){
return function() {
var tmp = this._super;
// add a new ._super() method that is the same method
// but on the super-class
this._super = _super[name];
// the method only need to be bound temporarily, so we
// remove it when we're done executing
var ret = fn.apply(this, arguments);
this._super = tmp;
return ret;
};
})(name, prop[name]) :
prop[name];
}
// the dummy class constructor
function class() {
// all construction is actually done in the init method
if ( !initializing && this.init )
this.init.apply(this, arguments);
}
// populate our constructed prototype object
class.prototype = prototype;
// enforce the constructor to be what we expect
class.prototype.constructor = class;
// and make this class extendable
class.extend = arguments.callee;
return class;
};
})();
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