LazyMan

實現函數LazyMan，使得：

LazyMan('Hank'); 輸出
Hi Hank!

LazyMan('Hank').eat('dinner');輸出
Hi Hank!
Eat dinner!

LazyMan('Hank').sleep(5).eat('dinner'); 輸出
Hi Hank!
//等待五秒
Eat dinner!

LazyMan('Hank').sleepFirst(5).eat('dinner');輸出
//等待五秒
Hi Hank!
Eat dinner!

實現代碼：

function LazyMan(name) {
    lp.taskList.push('Hi ' + name + '!');
    return lp.exe();
}

var lp = LazyMan.prototype;

lp.taskList = [];     

lp.eat = function(v) {
    lp.taskList.push('Eat ' + v + '!');
    return lp.exe();
}


lp.sleep = function(t) {
    lp.taskList.push('sleep ' + t);
    return lp.exe();

}

lp.sleepFirst = function(t) {
    lp.taskList.unshift('sleep ' + t);
    return lp.exe();
}

lp.taskStart = false;

lp.exe = function() {
    var that = this;
    if(!lp.taskStart) {
        lp.taskStart = true;
        setTimeout(function() {
            doTask(lp.taskList);
            that.taskList = [];
        }, 0);
    }
    return lp;
}


function doTask(taskList) {
    if(taskList.length) {
        var task = taskList.shift();
        if(task.indexOf('sleep') !== -1) {
            var match = task.split(' ');
            var t = parseInt(match[1]);
            setTimeout(function(){
                doTask(taskList);
            }, t * 1000);
        } else {
            console.log(task);
            doTask(taskList);
        }
    }
}

// LazyMan('Hank');
// LazyMan('Hank').eat('dinner');
// LazyMan('Hank').sleep(5).eat('dinner');
LazyMan('Hank').sleepFirst(5).eat('dinner');