实际情况来看，还是yield很爽
转自我的博客：http://www.cnblogs.com/htoooth/p/5595923.html
0 引言
最近公司有一个 php 的项目，要 port 到 node.js 来。我之前没有接触过这个项目，整个项目使用的是 yaf 框架。整个项目流程是调用服务端的业务数据，然后拼装数据，返回给前端；前端没有做到前后端分离，还有很多的页面在服务器端进行渲染 。
1 难度
1.1 php
php 之前没有写过几行代码，但是还能看懂。yaf 也没有接触过，只到听说的程度。然后还要把一个商品的详情页面从 php 导成 js 的，我觉得难度很大，因为接口竟然没有文档，只能看着 php 代码来了解。看了两天，有点门路了，开始动手。
1.2 js
nodejs使用的是 express 框架，框架不是我选的，公司有架构师选择，只能听命。最主要的是 express 确实不难。
1.3 再次申明
接手这一个项目我对这个项目的业务内容知识为零，同志们想想怎么把php导到js.
2 核心：php是同步的，js是异步
这个工作中，最有意思的是，php 是同步的，js 是异步的，把一大把同步的 php 代码导成异步的 js，这不就是证明 php 是不是最好的语言的战场吗？
各位，你们觉得这个事该怎么做快？
2.1 思路
当时，我就想到找个人好好给我讲讲这个项目的结构阿，字段啊，什么的？发现这样不行，为什么呢？
- 没有文档，包括接口
- 别人都很忙，没有时间给你讲
- 给自己的时间也不多（要在一个星期内搞定）
- 给你讲了一大堆业务，你也记不住
于是，我就直接上代码了，决定先写代码，业务知识什么以后再补。于是这场战役就是不关业务，较纯的关于代码的比较了。
2.2 如何做-代码
导代码，其实难度不大，就语言而言，php 和 js 相差不大，php 中也就array难以理解，因为能代表两种数据结构，返回值的时候就要好好看看，到底是返回 [] 还是 {}，就这个犯了不少错，其它的就一般般了。
重点是 php 中对 业务API的访问是同步的，那叫一个简单，调用一个函数就可以了。而在 js 中就有一个大问题，js是异步的，你必须将使用结果写在回调中。一个回调还是没有问题，问题是一个函数中有多异步调用，这我还能忍。最后面一个问题直接击垮了我，因为异步，打断了写代码结构层次，而我又不懂业务，接不上了业务逻辑，这就要我了解业务，可惜基于上面的原因不行啊。
有人会说 promise 能解决你的问题，promise 顺序，但是怎么访问变量啊，几十个变量的修改，你是不是都要放在then中，还有是放在全局变量中，关键是then也破坏了整体代码结构，一眼看过去全是then，最后我也不得不放弃这个方案。
一直说async/await解决了回调的问题，自己也试过，挺好的。可是项目不让用啊。
直到我发现了co，随后又发现 bludbird 的 Promise.coroutine，才解决了我的一些问题，因为我就需要直译啊，就是照着php翻译到js过去。对比一下代码：
2.3 php业务代码
public static function getProductInfo($productId, $goodsId, $uid, $vipLevel = 0, $productSkn = null)
{
$goodsInfo = array();
$statGoodsInfo = array();
$banner = array();
$baseInfo = ItemData::baseInfo($productId, $uid, $productSkn);//异步
if(empty($baseInfo['productName']) && empty($baseInfo['erpProductId']) && empty($baseInfo['productPriceBo'])) {
return array();
}
$baseInfo['uid'] = $uid;
$productId = $baseInfo['id'];
$goodsInfo['name'] = $baseInfo['productName'];
$goodsInfo['skn'] = $baseInfo['erpProductId'];
$goodsInfo['productId'] = $productId;
$goodsInfo['maxSortId'] = $baseInfo['maxSortId'];
$goodsInfo['smallSortId'] = $baseInfo['smallSortId'];
$goodsInfo['promotionId'] = $baseInfo['isPromotion'];
$goodsInfo['goCartUrl'] = Helpers::url('/shopping/cart');
$brandId = 0;
//设置并发请求数据
self::setMultiResourceByProductBaseInfo($baseInfo);//异步
if(isset($baseInfo['brand']['id'])) {
$brandId = $baseInfo['brand']['id'];
}
//收藏喜欢
$favoriteData = self::getProductFavoriteData($uid, $productId, $brandId);//异步
// 商品标签
$goodsInfo['tags'] = self::getTagsDataByProductInfo($baseInfo);//异步
// 商品促销短语
if (!empty($baseInfo['salesPhrase'])) {
$goodsInfo['saleTip'] = $baseInfo['salesPhrase'];
}
// 商品价格
if (isset($baseInfo['productPriceBo'])) {
$goodsInfo['marketPrice'] = $baseInfo['productPriceBo']['formatMarketPrice'];
$goodsInfo['hasOtherPrice'] = true;//非市场价格
$goodsInfo['salePrice'] = $baseInfo['productPriceBo']['formatSalesPrice'];
if($goodsInfo['marketPrice'] == $goodsInfo['salePrice']) {//价格相同，只显示市场价格
unset($goodsInfo['salePrice']);
$goodsInfo['hasOtherPrice'] = false;
}
}
//VIP数据
$goodsInfo['vipPrice'] = self::getVipDataByProductBaseInfo($baseInfo, $vipLevel, $uid);//异步
//促销活动banner
$goodsInfo['activity'] = self::getActivityDataByProductBaseInfo($baseInfo);//异步
if (isset($baseInfo['productPriceBo']['yohoCoinNum']) && $baseInfo['productPriceBo']['yohoCoinNum'] !== 0) {
array_push($goodsInfo['activity'],
array('type' => '返YOHO币', 'des' => '每件返 ' . $baseInfo['productPriceBo']['yohoCoinNum'] . '个 YOHO币')
);
}
// 上市期
if (isset($baseInfo['expectArrivalTime']) && !empty($baseInfo['expectArrivalTime'])) {
$goodsInfo['arrivalDate'] = $baseInfo['expectArrivalTime'] . '月';
$goodsInfo['presalePrice'] = $baseInfo['productPriceBo']['formatSalesPrice'];
unset($goodsInfo['salePrice']);
$goodsInfo['hasOtherPrice'] = false;
}
//商品咨询和评论数据
$consultComment = self::getConsultCommentDataByProductInfo($baseInfo);//异步
// 品牌信息
if (!empty($baseInfo['brand'])) {
$goodsInfo['brandImg'] = Helpers::getImageUrl($baseInfo['brand']['brandIco'], 47, 47);
$goodsInfo['brandName'] = $baseInfo['brand']['brandName'];
$goodsInfo['brandUrl'] = Helpers::url('', array(), $baseInfo['brand']['brandDomain']);
$banner = self::getBrandDataByProductBaseInfo($baseInfo);//异步
if(isset($banner['isCollect']) && isset($favoriteData['brand'])) {
$banner['isCollect'] = $favoriteData['brand'];
}
}
//sku商品信息
$skuData = self::getSkuDataByProductBaseInfo($baseInfo);//异步
$goodsInfo['img'] = $skuData['defaultImage'];
$goodsInfo['colors'] = $skuData['skuGoods'];
$totalStorageNum = $skuData['totalStorageNum'];
// 是否收藏
$goodsInfo['isCollect'] = $favoriteData['product'];
// 限购商品
if ($baseInfo['isLimitBuy'] === 'Y') {
// 是否开售
$isBeginSale = (isset($baseInfo['saleStatus']) && $baseInfo['saleStatus'] == 1);
// 限购商品有关的展示状态
$showStatus = 1;
if (isset($baseInfo['showStatus'])) {
$showStatus = intval($baseInfo['showStatus']);
}
$fashTopGoods = self::getFashionTopGoodsStatus($uid, $showStatus, $isBeginSale);//异步
//潮流尖货状态
$goodsInfo['fashionTopGoods'] = array(
'getLimitedCode' => $fashTopGoods['getLimitedCode'],//限购码状态
'hasLimitedCode' => $fashTopGoods['hasLimitedCode'],//是否已经获取限购码
'limitedCodeSoldOut'=> $fashTopGoods['limitedCodeSoldOut'],//限购码是否已经抢光
'getLimitedCodeDis' => $fashTopGoods['getLimitedCodeDis'],//限购码是否失效
);
if($fashTopGoods['soldOut']) {
$goodsInfo['soldOut'] = $fashTopGoods['soldOut'];
$totalStorageNum = 0;//改总数为已售磬
} else {
$goodsInfo['openSoon'] = $fashTopGoods['openSoon'];//即将开售
$goodsInfo['dis'] = $fashTopGoods['dis'];//是否失效
$goodsInfo['buyNow'] = $fashTopGoods['buyNow'];//是否立即购买
}
}
$soldOut = $baseInfo['status'] == 0 || $totalStorageNum === 0;
$notForSale = $baseInfo['attribute'] == 2;//非卖品
$virtualGoods = $baseInfo['attribute'] == 3;//虚拟商品
if (!$soldOut && !$notForSale && !$virtualGoods) {
$goodsInfo['addToCart'] = true;
//立即购买或者即将开售存在
if((isset($goodsInfo['buyNow']) && $goodsInfo['buyNow']) ||
(isset($goodsInfo['openSoon']) && $goodsInfo['openSoon'])) {
unset($goodsInfo['addToCart']);
}
}// 非卖品
elseif ($notForSale) {
$goodsInfo['notForSale'] = true;
}
// 已售磬
elseif ($soldOut) {
$goodsInfo['soldOut'] = true;
unset($goodsInfo['fashionTopGoods']);
}
//虚拟商品
else if($virtualGoods) {
$goodsInfo['buyNow'] = true;//是否立即购买
$goodsInfo['buyNowBase'] = Helpers::url('/ticket', array(), 'shopping');
$goodsInfo['virtualGoods'] = $virtualGoods;
if(isset($goodsInfo['salePrice'])) {
$goodsInfo['advancePrice'] = $goodsInfo['salePrice'];//先行价格
unset($goodsInfo['salePrice']);
}
}
//去掉即将售罄
if(empty($totalStorageNum) || $soldOut) {
if(isset($goodsInfo['tags']['isFew'])) {
unset($goodsInfo['tags']['isFew']);//去掉即将售罄
}
}
//分享相关
$goodsInfo['weixinUrl'] = Helpers::url($_SERVER['REQUEST_URI'], array(),'item');
$goodsInfo['sharedTitle'] = $goodsInfo['name'];
$goodsInfo['shareImg'] = $goodsInfo['img'];
$goodsInfo['shareDesc'] = $baseInfo['phrase'];
//统计需要的商品信息
$statGoodsInfo['uid'] = $uid;
$statGoodsInfo['skn'] = $baseInfo['erpProductId'];
$statGoodsInfo['productId'] = $productId;
$statGoodsInfo['productName'] = str_replace("'", "’",$goodsInfo['name']);
$statGoodsInfo['brandName'] = empty($goodsInfo['brandName'])? '' : str_replace("'", "’", $goodsInfo['brandName']);
$statGoodsInfo['marketPrice'] = str_replace('¥', '', $goodsInfo['marketPrice']);
if(isset($goodsInfo['salePrice'])) {
$statGoodsInfo['salePrice'] = str_replace('¥', '', $goodsInfo['salePrice']);
} else {
$statGoodsInfo['salePrice'] = str_replace('¥', '', $goodsInfo['marketPrice']);
}
if (!empty($banner['brandId'])) {
$domainBrand = BrandsModel::getBrandByDomain($banner['brandDomain']);
if (!empty($domainBrand['type']) && !empty($domainBrand['shopId'])) {
switch (intval($domainBrand['type'])) {
case 1:
//多品店不显示
$banner = array();
break;
case 2:
//单品店显示新版的店铺banner
$basisData = ShopModel::basisTemplate($domainBrand['shopId']);
$banner['bgImg'] = empty($basisData['shopTopBanner']['banner']) ?
$banner['bgImg'] : $basisData['shopTopBanner']['banner'];
break;
}
}
}
$statGoodsInfo['imageUrl'] = $goodsInfo['img'];
$statGoodsInfo['productUrl'] = $goodsInfo['weixinUrl'];
$statGoodsInfo['smallSortId'] = $goodsInfo['smallSortId'];
$statGoodsInfo['soldOut'] = intval($soldOut);
return array('goodsInfo'=> $goodsInfo,'consultComment' => $consultComment, 'banner'=> $banner,'statGoodsInfo' => $statGoodsInfo);
}
标异步的地方在函数中有十几处，你怎样解决呢？看懂业务后重构？
2.4 导成 javascript 的业务代码
这是js代码，使用 yield 解决问题
const detailDataPkg = (origin, uid, vipLevel, ua) => {
return co(function*() {
let result = {}; // 结果输出
// 商品名称
if (!origin.productName) {
return result;
}
origin.uid = uid;
result.name = origin.productName;
result.skn = origin.erpProductId;
result.productId = origin.id;
result.maxSortId = origin.maxSortId;
result.smallSortId = origin.smallSortId;
result.promotionId = origin.isPromotion;
result.goCartUrl = helpers.urlFormat('/shopping/cart');
// 接口处理数据，设置并发请求数据
yield setMultiResourceByProductBaseInfo(origin);
let brandId = 0;
if (origin.brand.id) {
brandId = origin.brand.id;
}
// 处理收藏喜欢数据
let favoriteData = yield getProductFavoriteData(uid, result.productId, brandId);
// 商品标签
result.tags = getTagsDataByProductInfo(origin);
// 商品促销短语
if (origin.salesPhase) {
result.saleTip = origin.salesPhrase;
}
// 商品价格
if (origin.productPriceBo) {
result.marketPrice = origin.productPriceBo.formatMarketPrice;
result.hasOtherPrice = true;
result.salePrice = origin.productPriceBo.formatSalesPrice;
if (result.marketPrice === result.salePrice) {
delete result.salePrice;
result.hasOtherPrice = false;
}
}
// VIP数据
result.vipPrice = getVipDataByProductBaseInfo(origin, vipLevel, uid);
// 促销活动banner
result.activity = yield getActivityDataByProductBaseInfo(origin);
const C_VALUE = {
type: '返YOHO币',
des: '每件返 ',
rest: '个 YOHO币'
};
if (origin.productPriceBo.yohoCoinNum && origin.productPriceBo.yohoCoinNum !== 0) {
result.activity.push({
type: C_VALUE.type,
des: `${C_VALUE.des}${origin.productPriceBo.yohoCoinNum}${C_VALUE.rest}`
});
}
// 上市期
if (origin.expectArrivalTime) {
result.arrivalDate = `${origin.expectArrivalTime}月`;
result.presalePrice = origin.productPriceBo.formatSalesPrice;
delete result.salePrice;
result.hasOtherPrice = false;
}
// 商品咨询和评论数据，当前为空
let consultComment = getConsultCommentDataByProductInfo(origin);
// 品牌信息
let banner = null;
if (origin.brand) {
result.brandImg = helpers.image(origin.brand.brandIco, 47, 47);
result.brandName = origin.brand.brandName;
result.brandUrl = helpers.urlFormat('', {}, origin.brand.brandDomain);
banner = yield getBrandDataByProductBaseInfo(origin);
if (banner.isCollect && favoriteData.brand) {
banner.isCollect = favoriteData.brand;
}
}
// sku商品信息
let skuData = getSkuDataByProductBaseInfo(origin);
result.img = skuData.defaultImage;
result.colors = skuData.skuGoods;
let totalStorageNum = skuData.totalStorageNum;
// 是否收藏
result.isCollect = favoriteData.product;
if (origin.isLimitBuy === 'y') {
// 是否开售
let isBeginSale = !!(origin.saleStatus && origin.saleStatus === 1);
// 限购商品有关的展示状态
let showStatus = 1;
if (origin.showStatus) {
showStatus = parseInt(origin.showStatus);
}
let fashTopGoods = getFashionTopGoodsStatus(uid, showStatus, isBeginSale);
result.fashTopGoods = {
getLimitedCode: fashTopGoods.getLimitedCode, // 限购码状态
hasLimitedCode: fashTopGoods.hasLimitedCode, // 是否已经获取限购码
limitedCodeSoldOut: fashTopGoods.limitedCodeSoldOut, // 限购码是否已经抢光
getLimitedCodeDis: fashTopGoods.getLimitedCodeDis // 限购码是否失效
};
if (fashTopGoods.soldOut) {
result.soldOut = fashTopGoods.soldOut;
totalStorageNum = 0; // 改总数为已售磬
} else {
result.openSoon = fashTopGoods.openSoon; // 即将开售
result.dis = fashTopGoods.dis; // 是否失效
result.buyNow = fashTopGoods.buyNow; // 是否立即购买
}
}
let soldOut = !!(origin.status === 0 || totalStorageNum === 0);
let notForSale = origin.attribute === 2; // 非卖品
let virtualGoods = origin.attribute === 3; // 虚拟商品
if (!soldOut && !notForSale && !virtualGoods) {
result.addToCart = true;
// 立即购买或者即将开售存在
if (result.buyNow || result.openSoon) {
delete result.addToCart;
}
} else if (notForSale) {
// 非卖品
result.notForSale = true;
} else if (soldOut) {
// 已售磬
result.soldOut = true;
delete result.fashTopGoods;
} else if (virtualGoods) {
// 虚拟商品
result.buyNow = true; // 是否立即购买
result.buyNowBase = helpers.urlFormat('/ticket', {}, 'shopping');
result.virtualGoods = virtualGoods;
if (result.salePrice) {
result.advancePrice = result.salePrice; // 先行价格
delete result.salePrice;
}
}
// 去掉即将售罄
if (totalStorageNum || soldOut) {
if (result.tags.isFew) {
delete result.tags.isFew; // 去掉即将售罄
}
}
// 分享相关，产品的链接
result.weixinUrl = helpers.urlFormat(origin.productUrl, {}, 'item');
result.shareTitle = result.name;
result.shareImg = result.img;
result.shareDesc = result.phrase;
// 统计需要的商品信息
let statGoodsInfo = {};
statGoodsInfo.uid = uid;
statGoodsInfo.skn = origin.erpProductId;
statGoodsInfo.productId = origin.id;
statGoodsInfo.productName = result.name.replace('\'', '’');
statGoodsInfo.brandName = (result.brandName || '').replace('\'', '’');
statGoodsInfo.marketPrice = result.marketPrice.replace('¥', '');
if (result.salePrice) {
statGoodsInfo.salePrice = result.salePrice.replace('¥', '');
} else {
statGoodsInfo.salePrice = result.marketPrice.replace('¥', '');
}
if (banner.brandId) {
let domainBrand = yield BrandData.getBrandByDomainAsync(banner.brandDomain);
if (domainBrand.type && domainBrand.shopId) {
switch (parseInt(domainBrand.type)) {
case 1:
{
// 多品店不显示
banner = [];
break;
}
case 2:
{
// TODO:单品店显示新版的店铺banner,item.php 210
let basisData = ShopModel.basisTemplate(domainBrand.shopId);
banner.bgImg = basisData.shopTopBanner.banner || banner.bgImg;
break;
}
}
}
}
statGoodsInfo.imageUrl = result.img;
statGoodsInfo.productUrl = result.weixinUrl;
statGoodsInfo.smallSortId = result.smallSortId;
statGoodsInfo.soldOut = parseInt(soldOut);
return {
goodsInfo: result,
consultComment: consultComment,
banner: banner,
statGoodsInfo: statGoodsInfo
};
})();
};
大家可以看到，使用 yield 之后，代码几乎就是跟php完全一样，我在写的过程中，也了解到了业务，同时完成了任务，就是这样。
3 结论
语言之争没有必要，重要的怎样解决问题的。通过使用 yield 使我较快的完成这项任务，节省了大量的时间，而我也终于知道了为什么 yield 如此的有用，为什么大家想方设法的去解决回调问题，因为在没有达到一定量级时，你确实没有感觉到回调的痛苦。多了回调确实很麻烦。
6 回复
do not use co directly. use fn = co.wrap gen & treat fn as async fn. It will be easy to go to async/await & better understanding
你的外部api 返回的是不是 promise对象啊？ （我是小白）
//现阶段v8 引擎对 generator 的优化 简直可以和nvdia一拼 var start,end; function test() { start=new Date var a={} for (var i = 0; i < 10000000; i++) { a.value=i*(i-2) } end=new Date; console.log(end-start) } function test_quality() { start=new Date var a_value for (var i = 0; i < 10000000; i++) { a_value=i*(i-2) } end=new Date; console.log(end-start) }
function g_test() { start=new Date var a={} for (var i = 0; i < 10000000; i++) { a.value=i(i-2) } end=new Date; console.log(end-start) } function *g_test_quality() { start=new Date
for (let i = 0,a_value=0; i < 10000000; i++) {
a_value=i*(i-2)
}
end=new Date;
console.log(end-start)
} test(); test_quality(); (g_test()).next(); (g_test_quality()).next() // 结果 // 46 // 16 // 222 // 1667//amazing // [Finished in 2.2s]
@magicdawn Yes, yo are right. And I use bluebird's Promise.coroutine instead of TJ'co。They both are all most same. I don’t wrapper they because all api that return value are Promise.
co.wrap gen or bluebird.coroutine makes an API function that it’s result is a Promise instance. that’s not on the opposite side.
