js设计模式 -- 装饰模式

Function.prototype.before = function(beforeFn) {
	var slef = this;
	console.log(this);
	return function() {
		console.log(this);
		beforeFn.apply(this, arguments);
		return slef.apply(this, arguments)
	}
};
Function.prototype.after = function(afterFn) {
	var self = this;
	return function() {
		var res = self.apply(this, arguments);
		afterFn.apply(this, arguments);
		return res;
	}
};