编写高质量可维护的代码：数据建模

{"type":"doc","content":[{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"什么是数据建模"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"数据建模是一种用于定义和分析数据的要求和其需要的相应支持的信息系统的过程。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"随着前端页面的交互变得更加细腻复杂，原本存放于服务端的状态放置在了前端，类似 flux、redux、mobx、dva、rematch、vuex 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XX，再将参与该活动的商品在区域内进行上架。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"降低复杂度"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"在大部分情况下，特别是展示逻辑这块，前端不应该是重逻辑的。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"以商品为例，不同商品的营销类型背后隐藏着复杂的价格体系，尽管是同一种营销类型，商品在不同的状态展示的价格也不一定相同。你可以想象这背后的字段，以及计算规则。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"假如后端把这些字段、各种 "},{"type":"codeinline","content":[{"type":"text","text":"price"}]},{"type":"text","text":" 和规则一股脑抛给你，先不谈前后端对称问题，光挑字段都能让你目瞪狗呆。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https:\/\/static001.geekbang.org\/infoq\/ed\/ed77bb3db890773542c504b2cae5a785.webp","alt":"Image","title":null,"style":[{"key":"width","value":"75%"},{"key":"bordertype","value":"none"}],"href":null,"fromPaste":true,"pastePass":true}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"遇到类似情况更好的办法是："},{"type":"text","marks":[{"type":"strong"}],"text":"尽量避免在前端（用户端）去处理复杂的业务判断"},{"type":"text","text":"，在聚合层或者让后端同学给你处理好这些展示逻辑。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"特别是在 C 端场景下，数据直出显得更加重要，同时前端同学也有更多时间去做性能优化（早点下班不香么？）。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"另外一个好处是假如出现展示问题，你只要确定读取的字段正确，剩下的仅需一个人排查就够了；"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":"text"},"content":[{"type":"text","text":"\/\/ Bad\nconst switchPrice = product => {\n switch(product.status) {\n case 0:\n return product.priceA;\n case 1:\n return product.priceB;\n case 2:\n return product.priceB;\n default:\n return product.priceBase;\n }\n}\n\n \n\/\/ Good\n"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"逻辑分层"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"设计上需要区分应用逻辑（业务逻辑）和展示逻辑。应用层注重对领域层的调度，是业务逻辑的实现，展示层专注渲染和交互动作。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"在一个大型项目中，同一个 Model 可能被多处引用，你很难确定谁最终会对同一份数据进行怎样的操作。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"同时 Model 中仅保留数据源的抽象结构，而不修改数据源的内容。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":null},"content":[{"type":"text","text":"\/\/ 在视图层只做展示逻辑处理\n\/\/ 组件A\n...\n<>\n 日期：{format(res.date, 'YYYY-MM-DD')}\n\n\n\/\/ 组件B\n...\n<>\n 日期：{format(res.date, 'YYYY-MM')}\n"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"统一字段"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"在设计模型的时候，尽可能与后端保持统一字段。比如某些表单场景在回显和提交的时候要多一层转换，后期维护会带来多一层心智负担。在前后端分离的开发模式下，不一定能保证后端会先给出字段，我的习惯是标记字段，等联调的时候全局替换一下就行了。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"简化字段、明确语义、改变不合理的前后端交互是做好数据建模的基础，否则你将花费大量时间去理解这些字段背后的含义和计算规则。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"小结"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"没有一个十全十美的数据模型可以适用任何需求场景，模型的落地需要综合考虑业务实际场景和技术选型。在构建模型的过程中，锻炼系统性思考能力、从更高的视角看待业务，才能创造出一个生命周期更长的模型。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"horizontalrule"},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"头图：Unsplash"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"作者：村雨"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"原文：https:\/\/mp.weixin.qq.com\/s\/RLuIX4O31PhcPCgMWivi7w"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"原文：编写高质量可维护的代码：数据建模"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"来源：政采云前端团队 - 微信公众号 [ID：Zoo-Team]"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"转载：著作权归作者所有。商业转载请联系作者获得授权，非商业转载请注明出处。"}]}]}