实际情况来看，还是yield很爽

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？

1. 没有文档，包括接口
2. 别人都很忙，没有时间给你讲
3. 给自己的时间也不多（要在一个星期内搞定）
4. 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。