LazyMan

      实现一个LazyMan，可以按照以下方式调用:
    LazyMan("Hank")输出:
    Hi! This is Hank!

    LazyMan("Hank").sleep(10).eat("dinner")输出
    Hi! This is Hank!
    //等待10秒..
    Wake up after 10
    Eat dinner~

    LazyMan("Hank").eat("dinner").eat("supper")输出
    Hi This is Hank!
    Eat dinner~
    Eat supper~

    LazyMan("Hank").sleepFirst(5).eat("supper")输出
    //等待5秒
    Wake up after 5
    Hi This is Hank!
    Eat supper

    以此类推。

 function LazyMan(name){
            return new _lazyman(name)
         }
        
         
         
         function _lazyman(name){
            this.tasks = [];
            var that = this;
            var fn = (function(name){
                return function(){
                    console.log("Hello I am " + name)
                    that.next()
                }
            })(name)
            this.tasks.push(fn);

            setTimeout(function(){
                that.next()
            },0)
         }
         
         
         _lazyman.prototype ={
            constructor:_lazyman,
            next:function(){
                var fn = this.tasks.shift()
                fn && fn()
            },
            sleep:function(time){
                var that = this;
                var fn = (function(time){
                    return function() {
                        console.log("sleep ..." +time)
                        setTimeout(function(){
                            that.next()
                        },time)
                    }
                })(time)
                this.tasks.push(fn);
                return this;
            },
            sleepfirst:function(time){
                var that = this;
                var fn = (function(time){
                    return function(){
                        console.log("sleep ..." +time)
                        setTimeout(function(){
                            that.next()
                        },time)
                    }
                })(time)
                this.tasks.unshift(fn)
                return this;
            },
            eat:function(something){
                var that = this;
                var fn = (function(something){
                    return function(){
                        console.log("Eat " + something);
                        that.next()
                    }
                })(something)
                this.tasks.push(fn)
                return this;
            }
         }
         LazyMan("Joe").sleepfirst(5000).eat("breakfast").sleep(3000).eat("dinner").sleep(3000).eat("supper");