洛阳火之焰 發表於 2020-12-13 11:21:00

前端元编程——使用注解加速你的前端开发

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<p>无论你用 React,Vue,还是 Angular,你还是要一遍一遍写相似的 CRUD 页面,一遍一遍,一遍一遍,一遍又一遍……</p>
<p>“天下苦秦久矣”~~</p>
<h2>前端开发的“痛点”在哪里?</h2>
<p class="ztext-empty-paragraph">&nbsp;</p>
<img src="https://pic3.zhimg.com/80/v2-dcfaca91b21958326ab0754eeca86d8a_1440w.jpg" width="660" class="origin_image zh-lightbox-thumb lazy" data-caption="" data-size="normal" data-rawwidth="660" data-rawheight="110" data-original="https://pic3.zhimg.com/v2-dcfaca91b21958326ab0754eeca86d8a_r.jpg" data-actualsrc="https://pic3.zhimg.com/v2-dcfaca91b21958326ab0754eeca86d8a_b.jpg" data-lazy-status="ok">
<p class="ztext-empty-paragraph">&nbsp;</p>
<p>现在的前端开发,我们有了世界一流的 UI 库 React,Vue,Angular,有了样式丰富的 UI 组件库 Tea (腾讯云 UI 组件库,类似 Antd Design), 有了方便强大的脚手架工具(例如,create react app)。但是我们在真正业务代码之前,通常还免不了写大量的样板代码。</p>
<p>现在的 CRUD 页面代码通常:</p>
<ol>
<li>太轻的“Model”或着“Service”,大多时候只是一些 API 调用的封装。</li>
<li>胖”View“,View 页面中有展示 UI 逻辑,生命周期逻辑,CRUD 的串联逻辑,然后还要塞满业务逻辑代码。</li>
<li>不同的项目业务逻辑不同,但是列表页,表单,搜索这三板斧的样板代码,却要一遍一遍占据着前端工程师的宝贵时间。</li>
</ol>
<p>特别是 CRUD 类应用的样板代码受限于团队风格,后端 API 风格,业务形态等,通常内在逻辑相似书写上却略有区别,无法通过一个通用的库或者框架来解决(上图中背景越深,越不容易有一个通用的方案)。</p>
<p>说好的“数据驱动的前端开发”呢?</p>
<p>对于这个“痛点”——怎么尽可能的少写模版代码,就是本文尝试解决的问题。</p>
<p>我们尝试使用 JavaScript 新特性<code>Decorator</code>和<code>Reflect</code>元编程来解决这个问题。</p>
<hr>
<h2>前端元编程</h2>
<blockquote>从 ECMAScript 2015 开始,JavaScript 获得了&nbsp;<code>Proxy</code>&nbsp;和&nbsp;<code>Reflect</code>&nbsp;对象的支持,允许你拦截并定义基本语言操作的自定义行为(例如,属性查找,赋值,枚举,函数调用等)。借助这两个对象,你可以在 JavaScript 元级别进行编程。<br>MDN</blockquote>
<p>在正式开始之前,我们先复习下<code>Decorator</code>和<code>Reflect</code>。</p>
<h3>Decorator</h3>
<p>这里我们简单介绍 Typescript 的<code>Decorator</code>,ECMAScript 中<code>Decorator</code>尚未定稿,但是不影响我们日常的业务开发(<em>Angular 同学就在使用 Typescript 的<code>Decorator</code></em>)。</p>
<p>简单来说,<code>Decorator</code>是可以标注修改类及其成员的新语言特性,使用<code>@expression</code>的形式,可以附加到,类、方法、访问符、属性、参数上。</p>
<p>TypeScript 中需要在<code>tsconfig.json</code>中增加<code>experimentalDecorators</code>来支持:</p>
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<pre><span style="color: rgba(0, 0, 0, 1)">{
    </span>"compilerOptions"<span style="color: rgba(0, 0, 0, 1)">: {
      </span>"target": "ES5"<span style="color: rgba(0, 0, 0, 1)">,
      </span>"experimentalDecorators": <span style="color: rgba(0, 0, 255, 1)">true</span><span style="color: rgba(0, 0, 0, 1)">
    }
}</span></pre>
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<p>&nbsp;</p>
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<p>比如可以使用类修饰器来为类扩展方法。</p>
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<pre><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)"> offer type</span>
<span style="color: rgba(0, 0, 0, 1)">abstract class Base {
log() {}
}

</span><span style="color: rgba(0, 0, 255, 1)">function</span><span style="color: rgba(0, 0, 0, 1)"> EnhanceClass() {
</span><span style="color: rgba(0, 0, 255, 1)">return</span> <span style="color: rgba(0, 0, 255, 1)">function</span><span style="color: rgba(0, 0, 0, 1)"> (Target) {
    </span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> class extends Target {
      log() {
      console.log(</span>"---log---"<span style="color: rgba(0, 0, 0, 1)">);
      }
    };
};
}
@EnhanceClass()
class Person extends Base {}

const person </span>= <span style="color: rgba(0, 0, 255, 1)">new</span><span style="color: rgba(0, 0, 0, 1)"> Person();
person.log();

</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)"> ---log---</span></pre>
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<p>&nbsp;</p>
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<p>更多查看 typescript 官方的文档。</p>
<p>Handbook - Decorators</p>
<h3>Reflect</h3>
<p>Reflect 是 ES6 中就有的特性,大家可能对它稍微陌生,Vue3 中依赖 Reflect 和 Proxy 来重写它的响应式逻辑。</p>
<p>简单来说,<code>Reflect</code>是一个人内置的对象,提供了拦截 JavaScript 操作的方法。</p>
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<pre>const _list = ;
const pList </span>= <span style="color: rgba(0, 0, 255, 1)">new</span><span style="color: rgba(0, 0, 0, 1)"> Proxy(_list, {
get(target, key, receiver) {
    console.log(</span>"get value reflect:"<span style="color: rgba(0, 0, 0, 1)">, key);
    </span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> Reflect.get(target, key, receiver);
},
set(target, key, value, receiver) {
    console.log(</span>"set value reflect"<span style="color: rgba(0, 0, 0, 1)">, key, value);
    </span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> Reflect.set(target, key, value, receiver);
},
});
pList.push(</span>4<span style="color: rgba(0, 0, 0, 1)">);
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)"> get value reflect:push</span><span style="color: rgba(0, 128, 0, 1)">
//</span><span style="color: rgba(0, 128, 0, 1)"> get value reflect:length</span><span style="color: rgba(0, 128, 0, 1)">
//</span><span style="color: rgba(0, 128, 0, 1)"> set value reflect 3 4</span><span style="color: rgba(0, 128, 0, 1)">
//</span><span style="color: rgba(0, 128, 0, 1)"> set value reflect length 4</span></pre>
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<p>&nbsp;</p>
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<h3>Reflect Metadata</h3>
<p>Reflect Metadata 是 ES7 的一个提案,Typescript 1.5+就有了支持。要使用需要:</p>
<ul>
<li><code>npm i reflect-metadata --save</code></li>
<li>在&nbsp;<code>`tsconfig.json`</code>&nbsp;里配置&nbsp;<code>`emitDecoratorMetadata`</code>&nbsp;选项</li>
</ul>
<p>简单来说,Reflect Metadata 能够为对象添加和读取元数据。</p>
<p>如下可以使用内置的<code>design:key</code>拿到属性类型:</p>
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<pre><span style="color: rgba(0, 0, 255, 1)">function</span><span style="color: rgba(0, 0, 0, 1)"> Type(): PropertyDecorator {
</span><span style="color: rgba(0, 0, 255, 1)">return</span> <span style="color: rgba(0, 0, 255, 1)">function</span><span style="color: rgba(0, 0, 0, 1)"> (target, key) {
    const type </span>= Reflect.getMetadata("design:type"<span style="color: rgba(0, 0, 0, 1)">, target, key);
    console.log(`${key} type: ${type.name}`);
};
}

class Person extends Base {
@Type()
name: string </span>= ""<span style="color: rgba(0, 0, 0, 1)">;
}
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)"> name type: String</span></pre>
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<p>&nbsp;</p>
</div>
<h2>使用 Decorator,Reflect 减少样板代码</h2>
<p>回到正题——使用 Decorator 和 Reflect 来减少 CRUD 应用中的样板代码。</p>
<h3>什么是 CRUD 页面?</h3>
<p class="ztext-empty-paragraph">&nbsp;</p>
<img src="https://pic1.zhimg.com/80/v2-4f12ac0c3d003cb54970ee7eb73325c4_1440w.jpg" width="660" class="origin_image zh-lightbox-thumb lazy" data-caption="" data-size="normal" data-rawwidth="660" data-rawheight="248" data-original="https://pic1.zhimg.com/v2-4f12ac0c3d003cb54970ee7eb73325c4_r.jpg" data-actualsrc="https://pic1.zhimg.com/v2-4f12ac0c3d003cb54970ee7eb73325c4_b.jpg" data-lazy-status="ok">
<p class="ztext-empty-paragraph">&nbsp;</p>
<p>CRUD 页面无需多言,列表页展示,表单页修改 ……包括 API 调用, 都是围绕某个数据结构(图中<code>Person</code>)展开,增、删、改、查。</p>
<h3>基本思路</h3>
<p>基本思路很简单,就像上图,Model 是中心,我们就是借助<code>Decorator</code>和<code>Reflect</code>将 CRUD 页面所需的样板类方法属性元编程在 Model 上。进一步延伸数据驱动 UI的思路。</p>
<p class="ztext-empty-paragraph">&nbsp;</p>
<img src="https://pic2.zhimg.com/80/v2-de7df803b17387b4b49c20dd543e9edd_1440w.jpg" width="660" class="origin_image zh-lightbox-thumb lazy" data-caption="" data-size="normal" data-rawwidth="660" data-rawheight="239" data-original="https://pic2.zhimg.com/v2-de7df803b17387b4b49c20dd543e9edd_r.jpg" data-actualsrc="https://pic2.zhimg.com/v2-de7df803b17387b4b49c20dd543e9edd_b.jpg" data-lazy-status="ok">
<p class="ztext-empty-paragraph">&nbsp;</p>
<ol>
<li>借助 Reflect Matadata 绑定 CRUD 页面信息到 Model 的属性上</li>
<li>借助 Decorator 增强 Model,生成 CRUD 所需的夜班代码</li>
</ol>
<h3>Show Me The Code</h3>
<p>下文,我们用TypeScript和React为例,组件库使用腾讯Tea component&nbsp;解说这个方案。</p>
<p>首先我们有一个函数来生成不同业务的属性装饰函数。</p>
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<pre><span style="color: rgba(0, 0, 255, 1)">function</span> CreateProperDecoratorF&lt;T&gt;<span style="color: rgba(0, 0, 0, 1)">() {
const metaKey </span>=<span style="color: rgba(0, 0, 0, 1)"> Symbol();
</span><span style="color: rgba(0, 0, 255, 1)">function</span><span style="color: rgba(0, 0, 0, 1)"> properDecoratorF(config: T): PropertyDecorator {
    </span><span style="color: rgba(0, 0, 255, 1)">return</span> <span style="color: rgba(0, 0, 255, 1)">function</span><span style="color: rgba(0, 0, 0, 1)"> (target, key) {
      Reflect.defineMetadata(metaKey, config, target, key);
    };
}
</span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> { metaKey, properDecoratorF };
}</span></pre>
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<p>&nbsp;</p>
</div>
<p>一个类装饰器,处理通过数据装饰器收集上来的元数据。</p>
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<pre>export <span style="color: rgba(0, 0, 255, 1)">function</span><span style="color: rgba(0, 0, 0, 1)"> EnhancedClass(config: ClassConfig) {
</span><span style="color: rgba(0, 0, 255, 1)">return</span> <span style="color: rgba(0, 0, 255, 1)">function</span><span style="color: rgba(0, 0, 0, 1)"> (Target) {
    </span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> class EnhancedClass extends Target {};
};
}</span></pre>
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<p>&nbsp;</p>
</div>
<h3>API Model 映射</h3>
<p>TypeScript 项目中第一步自然是将后端数据安全地转换为<code>type</code>,<code>interface</code>或者<code>Class</code>,这里 Class 能在编译后在 JavaScript 存在,我们选用<code>Class</code>。</p>
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<pre><span style="color: rgba(0, 0, 0, 1)">export interface TypePropertyConfig {
handle</span>?: string |<span style="color: rgba(0, 0, 0, 1)"> ServerHandle;
}

const typeConfig </span>= CreateProperDecoratorF&lt;TypePropertyConfig&gt;<span style="color: rgba(0, 0, 0, 1)">();
export const Type </span>=<span style="color: rgba(0, 0, 0, 1)"> typeConfig.properDecoratorF;

@EnhancedClass({})
export class Person extends Base {
static sexOptions </span>= ["male", "female", "unknow"<span style="color: rgba(0, 0, 0, 1)">];

@Type({
    handle: </span>"ID"<span style="color: rgba(0, 0, 0, 1)">,
})
id: number </span>= 0<span style="color: rgba(0, 0, 0, 1)">;

@Type({})
name: string </span>= ""<span style="color: rgba(0, 0, 0, 1)">;

@Type({
    handle(data, key) {
      </span><span style="color: rgba(0, 0, 255, 1)">return</span> parseInt(data || "0"<span style="color: rgba(0, 0, 0, 1)">);
    },
})
age: number </span>= 0<span style="color: rgba(0, 0, 0, 1)">;

@Type({
    handle(data, key) {
      </span><span style="color: rgba(0, 0, 255, 1)">return</span> Person.sexOptions.includes(data) ? data : "unknow"<span style="color: rgba(0, 0, 0, 1)">;
    },
})
sex: </span>"male" | "female" | "unknow" = "unknow"<span style="color: rgba(0, 0, 0, 1)">;
}</span></pre>
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<p>&nbsp;</p>
</div>
<p>重点在<code>handle?: string | ServerHandle</code>函数,在这个函数处理 API 数据和前端数据的转换,然后在<code>constructor</code>中集中处理。</p>
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<pre>export <span style="color: rgba(0, 0, 255, 1)">function</span><span style="color: rgba(0, 0, 0, 1)"> EnhancedClass(config: ClassConfig) {
</span><span style="color: rgba(0, 0, 255, 1)">return</span> <span style="color: rgba(0, 0, 255, 1)">function</span><span style="color: rgba(0, 0, 0, 1)"> (Target) {
    </span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> class EnhancedClass extends Target {
      constructor(data) {
      super(data);
      Object.keys(</span><span style="color: rgba(0, 0, 255, 1)">this</span>).forEach((key) =&gt;<span style="color: rgba(0, 0, 0, 1)"> {
          const config: TypePropertyConfig </span>=<span style="color: rgba(0, 0, 0, 1)"> Reflect.getMetadata(
            typeConfig.metaKey,
            </span><span style="color: rgba(0, 0, 255, 1)">this</span><span style="color: rgba(0, 0, 0, 1)">,
            key
          );
          </span><span style="color: rgba(0, 0, 255, 1)">this</span> =<span style="color: rgba(0, 0, 0, 1)"> config.handle
            </span>? <span style="color: rgba(0, 0, 255, 1)">typeof</span> config.handle === "string"
            ?<span style="color: rgba(0, 0, 0, 1)"> data
            : config.handle(data, key)
            : data;
      });
      }
    };
};
}</span></pre>
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<p>&nbsp;</p>
</div>
<h3>列表页 TablePage</h3>
<p>列表页中一般使用 Table 组件,无论是 Tea Component 还是 Antd Design Component 中,样板代码自然就是写那一大堆 Colum 配置了,配置哪些 key 要展示,表头是什么,数据转化为显示数据……</p>
<p>首先我们收集 Tea Table 所需的<code>TableColumn</code>类型的 column 元数据。</p>
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<pre>import { TableColumn } from "tea-component/lib/table"<span style="color: rgba(0, 0, 0, 1)">;
export type EnhancedTableColumn</span>&lt;T&gt; = TableColumn&lt;T&gt;<span style="color: rgba(0, 0, 0, 1)">;
export type ColumnPropertyConfig </span>= Partial&lt;EnhancedTableColumn&lt;any&gt;&gt;<span style="color: rgba(0, 0, 0, 1)">;

const columnConfig </span>= CreateProperDecoratorF&lt;ColumnPropertyConfig&gt;<span style="color: rgba(0, 0, 0, 1)">();
export const Column </span>=<span style="color: rgba(0, 0, 0, 1)"> columnConfig.properDecoratorF;

@EnhancedClass({})
export class Person extends Base {
static sexOptions </span>= ["male", "female", "unknow"<span style="color: rgba(0, 0, 0, 1)">];

id: number </span>= 0<span style="color: rgba(0, 0, 0, 1)">;

@Column({
    header: </span>"person name"<span style="color: rgba(0, 0, 0, 1)">,
})
name: string </span>= ""<span style="color: rgba(0, 0, 0, 1)">;

@Column({
    header: </span>"person age"<span style="color: rgba(0, 0, 0, 1)">,
})
age: number </span>= 0<span style="color: rgba(0, 0, 0, 1)">;

@Column({})
sex: </span>"male" | "female" | "unknow" = "unknow"<span style="color: rgba(0, 0, 0, 1)">;
}</span></pre>
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<p>&nbsp;</p>
</div>
<p>然后在 EnhancedClass 中收集,生成 column 列表。</p>
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<pre><span style="color: rgba(0, 0, 255, 1)">function</span> getConfigMap&lt;T&gt;<span style="color: rgba(0, 0, 0, 1)">(
F: any,
cachekey: symbol,
metaKey: symbol
): Map</span>&lt;string, T&gt;<span style="color: rgba(0, 0, 0, 1)"> {
</span><span style="color: rgba(0, 0, 255, 1)">if</span><span style="color: rgba(0, 0, 0, 1)"> (F) {
    </span><span style="color: rgba(0, 0, 255, 1)">return</span> F!<span style="color: rgba(0, 0, 0, 1)">;
}
const item </span>= <span style="color: rgba(0, 0, 255, 1)">new</span><span style="color: rgba(0, 0, 0, 1)"> F({});
F </span>= Object.keys(item).reduce((pre, cur) =&gt;<span style="color: rgba(0, 0, 0, 1)"> {
    const config: T </span>=<span style="color: rgba(0, 0, 0, 1)"> Reflect.getMetadata(metaKey, item, cur);
    </span><span style="color: rgba(0, 0, 255, 1)">if</span><span style="color: rgba(0, 0, 0, 1)"> (config) {
      pre.set(cur, config);
    }
    </span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> pre;
}, </span><span style="color: rgba(0, 0, 255, 1)">new</span> Map&lt;string, T&gt;<span style="color: rgba(0, 0, 0, 1)">());
</span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> F;
}

export </span><span style="color: rgba(0, 0, 255, 1)">function</span><span style="color: rgba(0, 0, 0, 1)"> EnhancedClass(config: ClassConfig) {
const cacheColumnConfigKey </span>= Symbol("cacheColumnConfigKey"<span style="color: rgba(0, 0, 0, 1)">);
</span><span style="color: rgba(0, 0, 255, 1)">return</span> <span style="color: rgba(0, 0, 255, 1)">function</span><span style="color: rgba(0, 0, 0, 1)"> (Target) {
    </span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> class EnhancedClass extends Target {
      : Map</span>&lt;string, ColumnPropertyConfig&gt; | <span style="color: rgba(0, 0, 255, 1)">null</span><span style="color: rgba(0, 0, 0, 1)">;
      </span><span style="color: rgba(0, 128, 0, 1)">/*</span><span style="color: rgba(0, 128, 0, 1)">*
       * table column config
       </span><span style="color: rgba(0, 128, 0, 1)">*/</span><span style="color: rgba(0, 0, 0, 1)">
      static get columnConfig(): Map</span>&lt;string, ColumnPropertyConfig&gt;<span style="color: rgba(0, 0, 0, 1)"> {
      </span><span style="color: rgba(0, 0, 255, 1)">return</span> getConfigMap&lt;ColumnPropertyConfig&gt;<span style="color: rgba(0, 0, 0, 1)">(
          EnhancedClass,
          cacheColumnConfigKey,
          columnConfig.metaKey
      );
      }

      </span><span style="color: rgba(0, 128, 0, 1)">/*</span><span style="color: rgba(0, 128, 0, 1)">*
       * get table colums
       </span><span style="color: rgba(0, 128, 0, 1)">*/</span><span style="color: rgba(0, 0, 0, 1)">
      static getColumns</span>&lt;T&gt;(): EnhancedTableColumn&lt;T&gt;<span style="color: rgba(0, 0, 0, 1)">[] {
      const list: EnhancedTableColumn</span>&lt;T&gt;[] =<span style="color: rgba(0, 0, 0, 1)"> [];
      EnhancedClass.columnConfig.forEach((config, key) </span>=&gt;<span style="color: rgba(0, 0, 0, 1)"> {
          list.push({
            key,
            header: key,
            ...config,
          });
      });
      </span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> list;
      }
    };
};
}</span></pre>
</div>
<p>&nbsp;</p>
<div class="highlight">
<pre><span style="font-family: &quot;PingFang SC&quot;, &quot;Helvetica Neue&quot;, Helvetica, Arial, sans-serif; font-size: 14px">Table 数据一般是分页,而且调用方式通常很通用,也可以在 EnhancedClass 中实现。</span></pre>
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<div class="highlight">
<div class="cnblogs_code">
<pre><span style="color: rgba(0, 0, 0, 1)">export interface PageParams {
pageIndex: number;
pageSize: number;
}

export interface Paginabale</span>&lt;T&gt;<span style="color: rgba(0, 0, 0, 1)"> {
total: number;
list: T[];
}
export </span><span style="color: rgba(0, 0, 255, 1)">function</span><span style="color: rgba(0, 0, 0, 1)"> EnhancedClass(config: ClassConfig) {
</span><span style="color: rgba(0, 0, 255, 1)">return</span> <span style="color: rgba(0, 0, 255, 1)">function</span><span style="color: rgba(0, 0, 0, 1)"> (Target) {
    </span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> class EnhancedClass extends Target {
      static async getList</span>&lt;T&gt;(params: PageParams): Promise&lt;Paginabale&lt;T&gt;&gt;<span style="color: rgba(0, 0, 0, 1)"> {
      const result </span>=<span style="color: rgba(0, 0, 0, 1)"> await getPersonListFromServer(params);
      </span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> {
          total: result.count,
          list: result.data.map((item) </span>=&gt; <span style="color: rgba(0, 0, 255, 1)">new</span><span style="color: rgba(0, 0, 0, 1)"> EnhancedClass(item)),
      };
      }
    };
};
}</span></pre>
</div>
<p>&nbsp;</p>
</div>
<p>自然我们封装一个更简易的 Table 组件。</p>
<div class="highlight">
<div class="cnblogs_code">
<pre>import { Table as TeaTable } from "tea-component/lib/table"<span style="color: rgba(0, 0, 0, 1)">;
import React, { FC, useEffect, useState } from </span>"react"<span style="color: rgba(0, 0, 0, 1)">;
import { EnhancedTableColumn, Paginabale, PageParams } from </span>"./utils"<span style="color: rgba(0, 0, 0, 1)">;
import { Person } from </span>"./person.service"<span style="color: rgba(0, 0, 0, 1)">;

</span><span style="color: rgba(0, 0, 255, 1)">function</span> Table&lt;T&gt;<span style="color: rgba(0, 0, 0, 1)">(props: {
columns: EnhancedTableColumn</span>&lt;T&gt;<span style="color: rgba(0, 0, 0, 1)">[];
getListFun: (param: PageParams) </span>=&gt; Promise&lt;Paginabale&lt;T&gt;&gt;<span style="color: rgba(0, 0, 0, 1)">;
}) {
const </span>= useState(<span style="color: rgba(0, 0, 255, 1)">false</span><span style="color: rgba(0, 0, 0, 1)">);
const </span>= useState&lt;Paginabale&lt;T&gt;&gt;<span style="color: rgba(0, 0, 0, 1)">();
const </span>= useState(1<span style="color: rgba(0, 0, 0, 1)">);
const </span>= useState(20<span style="color: rgba(0, 0, 0, 1)">);
useEffect(() </span>=&gt;<span style="color: rgba(0, 0, 0, 1)"> {
    (async () </span>=&gt;<span style="color: rgba(0, 0, 0, 1)"> {
      setIsLoading(</span><span style="color: rgba(0, 0, 255, 1)">true</span><span style="color: rgba(0, 0, 0, 1)">);
      const result </span>=<span style="color: rgba(0, 0, 0, 1)"> await props.getListFun({
      pageIndex,
      pageSize,
      });
      setIsLoading(</span><span style="color: rgba(0, 0, 255, 1)">false</span><span style="color: rgba(0, 0, 0, 1)">);
      setRecordData(result);
    })();
}, );
</span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> (
    </span>&lt;<span style="color: rgba(0, 0, 0, 1)">TeaTable
      columns</span>=<span style="color: rgba(0, 0, 0, 1)">{props.columns}
      records</span>={recordData ?<span style="color: rgba(0, 0, 0, 1)"> recordData.list : []}
      addons</span>=<span style="color: rgba(0, 0, 0, 1)">{[
      TeaTable.addons.pageable({
          recordCount: recordData </span>? recordData.total : 0<span style="color: rgba(0, 0, 0, 1)">,
          pageIndex,
          pageSize,
          onPagingChange: ({ pageIndex, pageSize }) </span>=&gt;<span style="color: rgba(0, 0, 0, 1)"> {
            setPageIndex(pageIndex </span>|| 0<span style="color: rgba(0, 0, 0, 1)">);
            setPageSize(pageSize </span>|| 20<span style="color: rgba(0, 0, 0, 1)">);
          },
      }),
      ]}
    </span>/&gt;
<span style="color: rgba(0, 0, 0, 1)">);
}

export </span><span style="color: rgba(0, 0, 255, 1)">default</span> Table;</pre>
</div>
<p>&nbsp;</p>
</div>
<ol>
<li><code>getConfigMap&lt;T&gt;(F: any, cachekey: symbol,metaKey: symbol): Map&lt;string,T&gt;</code>&nbsp;收集元数据到 Map</li>
<li><code>static getColumns&lt;T&gt;(): EnhancedTableColumn&lt;T&gt;[]</code>&nbsp;得到 table 可用 column 信息。</li>
</ol>
<div class="highlight">
<div class="cnblogs_code">
<pre>const App = () =&gt;<span style="color: rgba(0, 0, 0, 1)"> {
const columns </span>= Person.getColumns&lt;Person&gt;<span style="color: rgba(0, 0, 0, 1)">();
const getListFun </span>= useCallback((param: PageParams) =&gt;<span style="color: rgba(0, 0, 0, 1)"> {
    </span><span style="color: rgba(0, 0, 255, 1)">return</span> Person.getList&lt;Person&gt;<span style="color: rgba(0, 0, 0, 1)">(param);
}, []);
</span><span style="color: rgba(0, 0, 255, 1)">return</span> &lt;Table&lt;Person&gt; columns={columns} getListFun={getListFun} /&gt;;
};</pre>
</div>
<p>&nbsp;</p>
</div>
<p>效果很明显,不是吗? 7 行写一个 table page。</p>
<h3>Form 表单页</h3>
<p>表单,自然就是字段的 name,label,require,validate,以及提交数据的转换。</p>
<p>Form 表单我们使用Formik&nbsp;+ Tea Form Component +&nbsp;yup(数据校验)。Formik 使用 React Context 来提供表单控件所需的各种方法数据,然后借助提供的 Field 等组件,你可以很方便的封装你的业务表单组件。</p>
<div class="highlight">
<div class="cnblogs_code">
<pre>import React, { FC } from "react"<span style="color: rgba(0, 0, 0, 1)">;
import { Field, Form, Formik, FormikProps } from </span>"formik"<span style="color: rgba(0, 0, 0, 1)">;
import { Form as TeaForm, FormItemProps } from </span>"tea-component/lib/form"<span style="color: rgba(0, 0, 0, 1)">;
import { Input, InputProps } from </span>"tea-component/lib/input"<span style="color: rgba(0, 0, 0, 1)">;
import { Select } from </span>"tea-component/lib/select"<span style="color: rgba(0, 0, 0, 1)">;

type CustomInputProps </span>= Partial&lt;InputProps&gt; &amp;<span style="color: rgba(0, 0, 0, 1)">
Pick</span>&lt;FormItemProps, "label" | "name"&gt;<span style="color: rgba(0, 0, 0, 1)">;

type CustomSelectProps </span>= Partial&lt;InputProps&gt; &amp;<span style="color: rgba(0, 0, 0, 1)">
Pick</span>&lt;FormItemProps, "label" | "name"&gt; &amp;<span style="color: rgba(0, 0, 0, 1)"> {
    options: string[];
};

export const CustomInput: FC</span>&lt;CustomInputProps&gt; = (props) =&gt;<span style="color: rgba(0, 0, 0, 1)"> {
</span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> (
    </span>&lt;Field name={props.name}&gt;<span style="color: rgba(0, 0, 0, 1)">
      {({
      field, </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)"> { name, value, onChange, onBlur }</span>
      form: { touched, errors }, <span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)"> also values, setXXXX, handleXXXX, dirty, isValid, status, etc.</span>
<span style="color: rgba(0, 0, 0, 1)">      meta,
      }) </span>=&gt;<span style="color: rgba(0, 0, 0, 1)"> {
      </span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> (
          </span>&lt;<span style="color: rgba(0, 0, 0, 1)">TeaForm.Item
            label</span>=<span style="color: rgba(0, 0, 0, 1)">{props.label}
            required</span>=<span style="color: rgba(0, 0, 0, 1)">{props.required}
            status</span>={meta.touched &amp;&amp; meta.error ? "error"<span style="color: rgba(0, 0, 0, 1)"> : undefined}
            message</span>=<span style="color: rgba(0, 0, 0, 1)">{meta.error}
          </span>&gt;
            &lt;<span style="color: rgba(0, 0, 0, 1)">Input
            type</span>="text"<span style="color: rgba(0, 0, 0, 1)">
            {...field}
            onChange</span>={(value, ctx) =&gt;<span style="color: rgba(0, 0, 0, 1)"> {
                field.onChange(ctx.event);
            }}
            </span>/&gt;
          &lt;/TeaForm.Item&gt;
<span style="color: rgba(0, 0, 0, 1)">      );
      }}
    </span>&lt;/Field&gt;
<span style="color: rgba(0, 0, 0, 1)">);
};

export const CustomSelect: FC</span>&lt;CustomSelectProps&gt; = (props) =&gt;<span style="color: rgba(0, 0, 0, 1)"> {
</span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> (
    </span>&lt;Field name={props.name}&gt;<span style="color: rgba(0, 0, 0, 1)">
      {({
      field, </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)"> { name, value, onChange, onBlur }</span>
      form: { touched, errors }, <span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)"> also values, setXXXX, handleXXXX, dirty, isValid, status, etc.</span>
<span style="color: rgba(0, 0, 0, 1)">      meta,
      }) </span>=&gt;<span style="color: rgba(0, 0, 0, 1)"> {
      </span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> (
          </span>&lt;<span style="color: rgba(0, 0, 0, 1)">TeaForm.Item
            label</span>=<span style="color: rgba(0, 0, 0, 1)">{props.label}
            required</span>=<span style="color: rgba(0, 0, 0, 1)">{props.required}
            status</span>={meta.touched &amp;&amp; meta.error ? "error"<span style="color: rgba(0, 0, 0, 1)"> : undefined}
            message</span>=<span style="color: rgba(0, 0, 0, 1)">{meta.error}
          </span>&gt;
            &lt;<span style="color: rgba(0, 0, 0, 1)">Select
            {...field}
            options</span>={props.options.map((value) =&gt;<span style="color: rgba(0, 0, 0, 1)"> ({ value }))}
            onChange</span>={(value, ctx) =&gt;<span style="color: rgba(0, 0, 0, 1)"> {
                field.onChange(ctx.event);
            }}
            </span>/&gt;
          &lt;/TeaForm.Item&gt;
<span style="color: rgba(0, 0, 0, 1)">      );
      }}
    </span>&lt;/Field&gt;
<span style="color: rgba(0, 0, 0, 1)">);
};</span></pre>
</div>
<p>&nbsp;</p>
</div>
<p>照猫画虎,我们还是先收集 form 所需的元数据</p>
<div class="highlight">
<div class="cnblogs_code">
<pre>import * as Yup from "yup"<span style="color: rgba(0, 0, 0, 1)">;

export interface FormPropertyConfig {
validationSchema</span>?<span style="color: rgba(0, 0, 0, 1)">: any;
label</span>?<span style="color: rgba(0, 0, 0, 1)">: string;
handleSubmitData</span>?: (data: any, key: string) =&gt;<span style="color: rgba(0, 0, 0, 1)"> { : any };
required</span>?: <span style="color: rgba(0, 0, 255, 1)">boolean</span><span style="color: rgba(0, 0, 0, 1)">;
initValue</span>?<span style="color: rgba(0, 0, 0, 1)">: any;
options</span>?<span style="color: rgba(0, 0, 0, 1)">: string[];
}

const formConfig </span>= CreateProperDecoratorF&lt;FormPropertyConfig&gt;<span style="color: rgba(0, 0, 0, 1)">();
export const Form </span>=<span style="color: rgba(0, 0, 0, 1)"> formConfig.properDecoratorF;

@EnhancedClass({})
export class Person extends Base {
static sexOptions </span>= ["male", "female", "unknow"<span style="color: rgba(0, 0, 0, 1)">];

@Type({
    handle: </span>"ID"<span style="color: rgba(0, 0, 0, 1)">,
})
id: number </span>= 0<span style="color: rgba(0, 0, 0, 1)">;

@Form({
    label: </span>"Name"<span style="color: rgba(0, 0, 0, 1)">,
    validationSchema: Yup.string().required(</span>"Name is required"<span style="color: rgba(0, 0, 0, 1)">),
    handleSubmitData(data, key) {
      </span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> {
      : (data as string).toUpperCase(),
      };
    },
    required: </span><span style="color: rgba(0, 0, 255, 1)">true</span><span style="color: rgba(0, 0, 0, 1)">,
    initValue: </span>"test name"<span style="color: rgba(0, 0, 0, 1)">,
})
name: string </span>= ""<span style="color: rgba(0, 0, 0, 1)">;

@Form({
    label: </span>"Age"<span style="color: rgba(0, 0, 0, 1)">,
    validationSchema: Yup.string().required(</span>"Age is required"<span style="color: rgba(0, 0, 0, 1)">),
    handleSubmitData(data, key) {
      </span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> {
      : parseInt(data </span>|| "0"<span style="color: rgba(0, 0, 0, 1)">),
      };
    },
    required: </span><span style="color: rgba(0, 0, 255, 1)">true</span><span style="color: rgba(0, 0, 0, 1)">,
})
age: number </span>= 0<span style="color: rgba(0, 0, 0, 1)">;

@Form({
    label: </span>"Sex"<span style="color: rgba(0, 0, 0, 1)">,
    options: Person.sexOptions,
})
sex: </span>"male" | "female" | "unknow" = "unknow"<span style="color: rgba(0, 0, 0, 1)">;
}</span></pre>
</div>
<p>&nbsp;</p>
</div>
<p>有了元数据,我们可以在 EnhancedClass 中生成 form 所需:</p>
<ul>
<li>initialValues</li>
<li>数据校验的 validationSchema</li>
<li>各个表单组件所需的,name,label,required 等</li>
<li>提交表单的数据转换 handle 函数</li>
</ul>
<div class="highlight">
<div class="cnblogs_code">
<pre>export type FormItemConfigType&lt;T extends any&gt; =<span style="color: rgba(0, 0, 0, 1)"> {
: {
    validationSchema</span>?<span style="color: rgba(0, 0, 0, 1)">: any;
    handleSubmitData</span>?: FormPropertyConfig["handleSubmitData"<span style="color: rgba(0, 0, 0, 1)">];
    form: {
      label: string;
      name: string;
      required: </span><span style="color: rgba(0, 0, 255, 1)">boolean</span><span style="color: rgba(0, 0, 0, 1)">;
      message</span>?<span style="color: rgba(0, 0, 0, 1)">: string;
      options: string[];
    };
};
};

export </span><span style="color: rgba(0, 0, 255, 1)">function</span><span style="color: rgba(0, 0, 0, 1)"> EnhancedClass(config: ClassConfig) {
</span><span style="color: rgba(0, 0, 255, 1)">return</span> <span style="color: rgba(0, 0, 255, 1)">function</span><span style="color: rgba(0, 0, 0, 1)"> (Target) {
    </span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> class EnhancedClass extends Target {
      : Map</span>&lt;string, FormPropertyConfig&gt; | <span style="color: rgba(0, 0, 255, 1)">null</span><span style="color: rgba(0, 0, 0, 1)">;
      </span><span style="color: rgba(0, 128, 0, 1)">/*</span><span style="color: rgba(0, 128, 0, 1)">*
       * table column config
       </span><span style="color: rgba(0, 128, 0, 1)">*/</span><span style="color: rgba(0, 0, 0, 1)">
      static get formConfig(): Map</span>&lt;string, FormPropertyConfig&gt;<span style="color: rgba(0, 0, 0, 1)"> {
      </span><span style="color: rgba(0, 0, 255, 1)">return</span> getConfigMap&lt;FormPropertyConfig&gt;<span style="color: rgba(0, 0, 0, 1)">(
          EnhancedClass,
          cacheTypeConfigkey,
          formConfig.metaKey
      );
      }

      </span><span style="color: rgba(0, 128, 0, 1)">/*</span><span style="color: rgba(0, 128, 0, 1)">*
       * get form init value
       </span><span style="color: rgba(0, 128, 0, 1)">*/</span><span style="color: rgba(0, 0, 0, 1)">
      static getFormInitValues</span>&lt;T extends EnhancedClass&gt;(item?: T): Partial&lt;T&gt;<span style="color: rgba(0, 0, 0, 1)"> {
      const data: any </span>=<span style="color: rgba(0, 0, 0, 1)"> {};
      const _item </span>= <span style="color: rgba(0, 0, 255, 1)">new</span><span style="color: rgba(0, 0, 0, 1)"> EnhancedClass({});
      EnhancedClass.formConfig.forEach((config, key) </span>=&gt;<span style="color: rgba(0, 0, 0, 1)"> {
          </span><span style="color: rgba(0, 0, 255, 1)">if</span> (item &amp;&amp; key <span style="color: rgba(0, 0, 255, 1)">in</span><span style="color: rgba(0, 0, 0, 1)"> item) {
            data </span>=<span style="color: rgba(0, 0, 0, 1)"> item;
          } </span><span style="color: rgba(0, 0, 255, 1)">else</span> <span style="color: rgba(0, 0, 255, 1)">if</span> ("initValue" <span style="color: rgba(0, 0, 255, 1)">in</span><span style="color: rgba(0, 0, 0, 1)"> config) {
            data </span>=<span style="color: rgba(0, 0, 0, 1)"> config.initValue;
          } </span><span style="color: rgba(0, 0, 255, 1)">else</span><span style="color: rgba(0, 0, 0, 1)"> {
            data </span>= _item || ""<span style="color: rgba(0, 0, 0, 1)">;
          }
      });
      </span><span style="color: rgba(0, 0, 255, 1)">return</span> data as Partial&lt;T&gt;<span style="color: rgba(0, 0, 0, 1)">;
      }

      static getFormItemConfig</span>&lt;T extends EnhancedClass&gt;(overwriteConfig?<span style="color: rgba(0, 0, 0, 1)">: {
      : any;
      }): FormItemConfigType</span>&lt;T&gt;<span style="color: rgba(0, 0, 0, 1)"> {
      const formConfig: any </span>=<span style="color: rgba(0, 0, 0, 1)"> {};
      EnhancedClass.formConfig.forEach((config, key) </span>=&gt;<span style="color: rgba(0, 0, 0, 1)"> {
          formConfig </span>=<span style="color: rgba(0, 0, 0, 1)"> {
            form: {
            label: String(config.label </span>||<span style="color: rgba(0, 0, 0, 1)"> key),
            name: String(key),
            required: </span>!!<span style="color: rgba(0, 0, 0, 1)">config.validationSchema,
            options: config.options </span>||<span style="color: rgba(0, 0, 0, 1)"> [],
            ...overwriteConfig,
            },
          };
          </span><span style="color: rgba(0, 0, 255, 1)">if</span><span style="color: rgba(0, 0, 0, 1)"> (config.validationSchema) {
            formConfig.validationSchema </span>=<span style="color: rgba(0, 0, 0, 1)"> config.validationSchema;
          }
          </span><span style="color: rgba(0, 0, 255, 1)">if</span><span style="color: rgba(0, 0, 0, 1)"> (config.handleSubmitData) {
            formConfig.handleSubmitData </span>=<span style="color: rgba(0, 0, 0, 1)"> config.handleSubmitData;
          }
      });
      </span><span style="color: rgba(0, 0, 255, 1)">return</span> formConfig as FormItemConfigType&lt;T&gt;<span style="color: rgba(0, 0, 0, 1)">;
      }

      static handleToFormData</span>&lt;T extends EnhancedClass&gt;<span style="color: rgba(0, 0, 0, 1)">(item: T) {
      let data </span>=<span style="color: rgba(0, 0, 0, 1)"> {};
      EnhancedClass.formConfig.forEach((config, key) </span>=&gt;<span style="color: rgba(0, 0, 0, 1)"> {
          </span><span style="color: rgba(0, 0, 255, 1)">if</span><span style="color: rgba(0, 0, 0, 1)"> (item.hasOwnProperty(key)) {
            data </span>=<span style="color: rgba(0, 0, 0, 1)"> {
            ...data,
            ...(EnhancedClass.formConfig.get(key).handleSubmitData
                </span>?<span style="color: rgba(0, 0, 0, 1)"> EnhancedClass.formConfig.get(key).handleSubmitData(item, key)
                : {
                  : item </span>|| ""<span style="color: rgba(0, 0, 0, 1)">,
                  }),
            };
          }
      });
      </span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> data;
      }
    };
};
}</span></pre>
</div>
<p>&nbsp;</p>
<pre><span style="font-family: &quot;PingFang SC&quot;, &quot;Helvetica Neue&quot;, Helvetica, Arial, sans-serif; font-size: 14px"><br>在 FormPage 中使用</span></pre>
</div>
<div class="highlight">
<div class="cnblogs_code">
<pre>export const PersonForm: FC&lt;<span style="color: rgba(0, 0, 0, 1)">{
onClose: () </span>=&gt; <span style="color: rgba(0, 0, 255, 1)">void</span><span style="color: rgba(0, 0, 0, 1)">
}</span>&gt; = (props) =&gt;<span style="color: rgba(0, 0, 0, 1)"> {
const initialValues </span>= Person.getFormInitValues&lt;Person&gt;<span style="color: rgba(0, 0, 0, 1)">();
const formConfig </span>= Person.getFormItemConfig&lt;Person&gt;<span style="color: rgba(0, 0, 0, 1)">();
const schema </span>= Object.entries(formConfig).reduce((pre, ) =&gt;<span style="color: rgba(0, 0, 0, 1)"> {
    </span><span style="color: rgba(0, 0, 255, 1)">if</span><span style="color: rgba(0, 0, 0, 1)"> (value.validationSchema) {
      pre </span>=<span style="color: rgba(0, 0, 0, 1)"> value.validationSchema;
    }
    </span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> pre;
}, {});
const validationSchema </span>=<span style="color: rgba(0, 0, 0, 1)"> Yup.object().shape(schema);

</span><span style="color: rgba(0, 0, 255, 1)">function</span><span style="color: rgba(0, 0, 0, 1)"> onSubmit(values) {
    const data </span>=<span style="color: rgba(0, 0, 0, 1)"> Person.handleToFormData(values);
    setTimeout(() </span>=&gt;<span style="color: rgba(0, 0, 0, 1)"> {
      console.log(</span>"---send to server"<span style="color: rgba(0, 0, 0, 1)">, data);
      props.onClose();
    }, </span>10000<span style="color: rgba(0, 0, 0, 1)">);
}
</span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> (
    </span>&lt;<span style="color: rgba(0, 0, 0, 1)">Formik
      initialValues</span>=<span style="color: rgba(0, 0, 0, 1)">{initialValues}
      onSubmit</span>=<span style="color: rgba(0, 0, 0, 1)">{onSubmit}
      validationSchema</span>=<span style="color: rgba(0, 0, 0, 1)">{validationSchema}
    </span>&gt;<span style="color: rgba(0, 0, 0, 1)">
      {(formProps: FormikProps</span>&lt;any&gt;) =&gt;<span style="color: rgba(0, 0, 0, 1)"> {
      </span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> (
          </span>&lt;TeaForm&gt;
            &lt;CustomInput {...formConfig.name.form} /&gt;
            &lt;CustomInput {...formConfig.age.form} /&gt;
            &lt;CustomSelect {...formConfig.sex.form} /&gt;
            &lt;<span style="color: rgba(0, 0, 0, 1)">Button
            type</span>="primary"<span style="color: rgba(0, 0, 0, 1)">
            htmlType</span>="submit"<span style="color: rgba(0, 0, 0, 1)">
            onClick</span>={() =&gt;<span style="color: rgba(0, 0, 0, 1)"> {
                formProps.submitForm();
            }}
            </span>&gt;<span style="color: rgba(0, 0, 0, 1)">
            Submit
            </span>&lt;/Button&gt;
          &lt;/TeaForm&gt;
<span style="color: rgba(0, 0, 0, 1)">      );
      }}
    </span>&lt;/Formik&gt;
<span style="color: rgba(0, 0, 0, 1)">);
};</span></pre>
</div>
<p>&nbsp;</p>
</div>
<p>40 行,我们有了个一个功能完备表单页</p>
<span class="LinkCard-content"><span class="LinkCard-text"><span class="LinkCard-title" data-text="true">https://ts-model-decorator.stackblitz.io/</span></span></span>
<p>元编程减少样板代码Demo</p>
<span class="LinkCard-backdrop"><span class="LinkCard-content"><span class="LinkCard-text"><span class="LinkCard-title" data-text="true">https://github.com/yijian166/ts-model-decorator</span></span></span></span>
<h3>效果</h3>
<p>上文包含了不少的代码,但是大部头在如何将元数据转换成为页面组件可用的数据,也就是元编程的部分。</p>
<p>而业务页面,7 行的 Table 页面,40 行的 Form 页面,已经非常精简功能完备了。根据笔者实际项目中估计,可以节省至少 40%的代码量。</p>
<h2>元编程 vs. 配置系统</h2>
<p>写到尾声,你大概会想到某些配置系统,前端 CRUD 这个从古就有的需求,自然早就有方案,用的最多的就是配置系统,在这里不会过多讨论。</p>
<p>简单来说,就是一个单独的系统,配置类似上文的元信息,然后使用固定模版生成代码。</p>
<p>思路实际上和本文的元编程类似,只是元编程成本低,你不需要单独做一个系统,更加轻量灵活,元编程代码在运行时,想象空间更大……</p>
<h2>总结</h2>
<p>上面只是 table,form 页面的代码展示,由此我们可以引申到很多类似的地方,甚至 API 的调用代码都可以在元编程中处理。</p>
<p class="ztext-empty-paragraph">&nbsp;</p>
<img src="https://pic3.zhimg.com/80/v2-10164ecca9cd41b59da3065b6b1653ae_1440w.jpg" width="660" class="origin_image zh-lightbox-thumb lazy" data-caption="" data-size="normal" data-rawwidth="660" data-rawheight="410" data-original="https://pic3.zhimg.com/v2-10164ecca9cd41b59da3065b6b1653ae_r.jpg" data-actualsrc="https://pic3.zhimg.com/v2-10164ecca9cd41b59da3065b6b1653ae_b.jpg" data-lazy-status="ok">
<p class="ztext-empty-paragraph">&nbsp;</p>
<p>元编程——将元数据转换成为页面组件可用的数据,这部分恰恰可以在团队内非常好共享也需要共同维护的部分,带来的好处也很明显:</p>
<ul>
<li>最大的好处自然就是生产效率的提高了,而且是低成本的实现效率的提升(相比配置系统)。一些简单单纯的 CURD 页面甚至都不用写代码了。</li>
<li>更易维护的代码:</li>
<li>“瘦 View“,专注业务,</li>
<li>更纯粹的 Model,你可以和 redux,mobx 配合,甚至,你可以从 React,换成 Angular)</li>
<li>最后更重要的是,元编程是一个低成本,灵活,渐进的方案。它是一个运行时的方案,你不需要一步到罗马,徐徐图之 …… - ……</li>
</ul>
<img src="https://pic1.zhimg.com/80/v2-46b6c92eee2aa9c6c86df560bd87eee8_1440w.jpg" width="660" class="origin_image zh-lightbox-thumb lazy" data-size="normal" data-rawwidth="660" data-rawheight="148" data-original="https://pic1.zhimg.com/v2-46b6c92eee2aa9c6c86df560bd87eee8_r.jpg" data-actualsrc="https://pic1.zhimg.com/v2-46b6c92eee2aa9c6c86df560bd87eee8_b.jpg" data-lazy-status="ok">前端元编程,较少你的样板代码,加速前端开发
<p class="ztext-empty-paragraph">&nbsp;</p>
<p>最后,本文更多是一次实践,一种思路,一种元编程在前端开发中的应用场景,最重要的还是抛砖引玉,希望前端小伙伴们能形成自己团队的的元编程实践,来解放生产力,更快搬砖~~</p>
<p>&nbsp;转自https://zhuanlan.zhihu.com/p/274328551</p>
</div>
</div><p>喜欢这篇文章?欢迎打赏~~</p><p><img src="https://img2020.cnblogs.com/blog/1313648/202012/1313648-20201207210415386-746901846.png" alt="" loading="lazy"></p><p>&nbsp;</p><br><br>
来源:https://www.cnblogs.com/cangqinglang/p/14128127.html
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