lazyman 실현

 function _lazyman(name) {
 this.tasks = [];
 var self = this;
 var fn = function() {
 console.log("hi this is " + name);
 self.next();
 }
 this.tasks.push(fn);
 setTimeout(function() {
 self.next();
 }, 0);
 }
 //  next
 _lazyman.prototype.next = function() {
 // body...
 var fn = this.tasks.shift();
 fn && fn();
 };
 _lazyman.prototype.eat = function(name) {
 // body...
 var self = this;
 var fn = function() {
 console.log("eat " + name + " ~");
 self.next();
 }
 this.tasks.push(fn);
 //  
 return this;
 };
 _lazyman.prototype.sleep = function(time) {
 // body...
 var self = this;
 var fn = function() {
 setTimeout(function() {
 console.log("sleep " + time + "s ~");
 self.next();
 }, time * 1000);
 }
 this.tasks.push(fn);
 //  
 return this;
 };
 _lazyman.prototype.sleepFirst = function(time) {
 // body...
 var self = this;
 var fn = function() {
 setTimeout(function() {
 console.log("sleepFirst " + time + "s ~");
 self.next();
 }, time * 1000);
 }
 // unshift
 this.tasks.unshift(fn);
 //  
 return this;
 };
 //  
 function LazyMan(name) {
 return new _lazyman(name);
 }
 

 LazyMan('hahah').eat('dinner').sleep(10).eat('lunch').sleepFirst(5);
 // sleepFirst 10s
 // hi this is hahah
 // eat dinner
 // sleep 10s
 // eat lunch