nodejs 使用关键字yield 纯异步文件夹复制2.0

生活如麻

　　首先现在安装yflow 
　　yflow 借助es6 生成器函数来解决金字塔回调问题。
　　这个连接

http://faylai.iteye.com/blog/1924523
　　是我先前使用async 做的但是代码超长不好理解，写做困难。
　　比较下面的实现简直就是nodejs的曙光啊
　　---------------------------------------------------------------------------
　　首先安装 yflow 组建 ：npm install yflow

var yflow = require("yflow");
var FS = require("fs");
var fs = yflow.wrap(FS);
var path = require("path");
// 检测文件或者文件夹是否存在
var isExists = yflow.wrap(function (dir, cb) {
FS.exists(dir, function (isExist) {
cb(null, isExist);
});
});
// 创建多级目录
function mkdirs(p, mode, f, made) {
if (typeof mode === 'function' || mode === undefined) {
f = mode;
mode = 0777 & (~process.umask());
}
if (!made) {
made = null;
}
var cb = f || function () {};
if (typeof mode === 'string') {
mode = parseInt(mode, 8);
}
yflow(
function  * () {
p = path.resolve(p);
var startDir = p;
while (true) {
var exist = yield isExists(startDir);
if (exist) {
break;
} else {
startDir = path.dirname(startDir);
}
}
var slashees = p.split(startDir)[1].split(path.sep);
for (var i = 0; i < slashees.length; i++) {
var slashee = slashees.trim();
if (slashee != '') {
startDir = path.join(startDir, slashee);
yield fs.mkdir(startDir, mode);
}
}
})(f)
}
// 单个文件复制
function copyFile(file, toDir, cb) {
yflow(function  * () {
yield yflow.wrap(mkdirs)(toDir);
var reads = FS.createReadStream(file);
var writes = FS.createWriteStream(path.join(path.resolve(toDir), path.basename(file)));
reads.pipe(writes);
reads.on("end", function () {
writes.end();
});
})(cb);
}
//文件夹复制
function copyDir(from, to, cb) {
yflow(function  * () {
var stat = yield isExists(from);
stat = yield fs.stat(from);
if (stat.isFile()) {
yield yflow.wrap(copyFile)(from, to);
} else if (stat.isDirectory) {
var files = yield fs.readdir(from);
for (var i = 0; i < files.length; i++) {
var newFile = path.join(from, files);
stat = yield fs.stat(newFile);
if (stat.isFile()) {
yield yflow.wrap(copyFile)(newFile, to);
} else if (stat.isDirectory()) {
yield yflow.wrap(copyDir)(newFile, path.join(to, files));
}
}
}
})(cb);
}
　　测试代码如下：

copyDir("F:\\jar", "F:\\jar2", function (e) {
if (e) {
console.log(e.stack);
} else {
console.log("copy ok!");
}
})