JavaScript流程控制，关键是如何实现任务的顺序执行。

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。

。。。。。。。。。。。。。。

JavaScript流程控制，关键是如何实现任务的顺序执行。
创建一个任务队列，再调用next()函数来控制任务的顺序执行：

function _LazyMan(name) {
this.tasks = [];
var self = this;
var fn =(function(n){
var name = n;
return function(){
console.log("Hi! This is " + name + "!");
self.next();
}
})(name); //闭包，执行方法后，调用next方法
this.tasks.push(fn);
setTimeout(function(){
self.next();
}, 0); // 在下一个事件循环启动任务
}
/* 事件调度函数 */
_LazyMan.prototype.next = function() {
var fn = this.tasks.shift();
fn && fn();
}
_LazyMan.prototype.eat = function(name) {
var self = this;
var fn =(function(name){
return function(){
console.log("Eat " + name + "~");
self.next();
}
})(name);
this.tasks.push(fn);
return this; // 实现链式调用
}
_LazyMan.prototype.sleep = function(time) {
var self = this;
var fn = (function(time){
return function() {
setTimeout(function(){
console.log("Wake up after " + time + "s!");
self.next();
}, time * 1000);
}
})(time);
this.tasks.push(fn);
return this;
}
_LazyMan.prototype.sleepFirst = function(time) {
var self = this;
var fn = (function(time) {
return function() {
setTimeout(function() {
self.next(); console.log("Wake up after " + time + "s!");
}, time * 1000);
}
})(time);
this.tasks.unshift(fn);
return this;
}
function LazyMan(name){ //封装
return new _LazyMan(name);
}