SOURCE

const Man = function(){
    this.run = function(){
        console.log('跑步')
    }
}
const Decorator  = function(old){
    this.oldAbility = old.run
    this.fly = function(){
        console.log("具备飞行能力")
    }
    this.newAbility = function(){
        this.oldAbility()
        this.fly()
    }
} 
const man = new Man()
const superMan = new Decorator(man)
superMan.fly()