//非同步操作，序列有關聯（瀑布流模式）
//npm install async --save-dev
var async = require('async');
function exec() {
    async.waterfall(
        [
            function (done) {
                i = 0;
                setInterval(function () {
                    console.log("aaa==" + new Date());
                    i++;
                    if (i == 3) {
                        clearInterval(this);
                        done(null, 'one完畢');
                    }
                }, 1000);
            },
            function (preValue, done) {
                j = 0;
                setInterval(function () {
                    console.log(preValue + "bbb==" + new Date());
                    j++;
                    if (j == 3) {
                        clearInterval(this);
                        done(null, preValue + 'two完畢');
                    }
                }, 1000);
            }
        ], function (err, rs) {
            console.log(err);
            console.log(rs);
        }
    )
}

exec();
console.log("主程序執行完畢");