導語:Element UI[1] 是世界級最優秀的UI框架之一。這個優秀的框架有哪些我們能學習的優點呢?這篇文章將分享作者在查看這個框架倉庫源碼中認爲值得參考的技巧,建議配合element[2]源碼食用更佳。
技巧一:組件腳手架
腳手架在創建新組件的應用:規範代碼目錄,減少搬磚工作量 ,腳手架源碼實現:build/bin/new.js[3]
# 執行命令,參數說明
# componentname 組件名 必填
# chineseName 組將中文名 選填 ,不填默認取值componentname
# node build/bin/new.js componentname [chineseName] 命令說明
# 在element項目下執行
node build/bin/new.js helloworld 示例
腳手架處理結果:
-
1、組件樣式處理:
1.1 生成組件樣式 packages/theme-chalk/src/${componentname}.scss
1.2 樣式入口文件packages/theme-chalk/src/index.scss 導入改組件樣式
-
2、組件代碼處理:
2.1 生成組件代碼文件 :packages/componentname/index.js和packages/{componentname}/index.js和packages/componentname/index.js和packages/{componentname}/src/main.vue
2.2 新增組件的路徑信息導入到 components.json ,該文件是json對象,存放了組件的名字和組件入口路徑
-
3、生成組件文檔:
3.1 生成examlpes/docs/{i18n}/component.md, 其中,i18n=['en-US','es','fr-FR','zh-CN']
3.2 將新增的組件文檔的標題和路徑添加到 examples/nav.config.json,該文件是Element UI的組件文檔的目錄,保存了組件文檔的標題和路由
-
4、生成單元測試:
4.1 生成單元測試文件:test/unit/specs/component.spec.js
-
5、生成組件接口定義:
5.1 生成組件的描述文件:types/component.d.ts
5.2在types/element-ui.d.ts新增新組件的接口定義
一個優秀的組件,除了需要要把組件的代碼寫好,還有有單元測試、文檔說明,最好,也有有接口定義(這編譯器就有友好的使用提示),Element的組件起步就已經配齊了😄
技巧二:用代碼來生成代碼
源碼入口文件生成:Element UI 目前一共有80個組件,如果要導出這80個組件,那麼引入、導出和聲明Vue組件的代碼都要寫240次,而且,組件的增刪都要去修改入口文件。爲了減少這部分工作量,基於components.json[4]來生成入口文件的組件引入和導出。
components.json內容如下:
入口文件有三處代碼(引入,導出和聲名組件)都要重複了80次,下面以引入代碼語句作爲說明示例:
引入代碼示例:
/* Automatically generated by './build/bin/build-entry.js' */
import Pagination from '../packages/pagination/index.js';
import Dialog from '../packages/dialog/index.js';
import Autocomplete from '../packages/autocomplete/index.js';
import Dropdown from '../packages/dropdown/index.js';
import DropdownMenu from '../packages/dropdown-menu/index.js';
import DropdownItem from '../packages/dropdown-item/index.js';
import Menu from '../packages/menu/index.js';
/**省略 70多個組件導入**/
import CollapseTransition from 'element-ui/src/transitions/collapse-transition';
生成上述代碼,主要邏輯:讀入components.json作爲數據,然後模版拼接起來,具體實現如下:
var Components = require('../../components.json');
var render = require('json-templater/string');
var uppercamelcase = require('uppercamelcase');
var endOfLine = require('os').EOL;
// import 語句語法模版
var IMPORT_TEMPLATE = 'import {{name}} from \'../packages/{{package}}/index.js\';';
var ComponentNames = Object.keys(Components);
var includeComponentTemplate = [];
ComponentNames.forEach(name => {
var componentName = uppercamelcase(name);
includeComponentTemplate.push(
// 單條import生成語句
render(IMPORT_TEMPLATE, {
name: componentName,
package: name
})
);
});
console.info(includeComponentTemplate.join(endOfLine))
生成代碼的實現:build/bin/build-entry.js[5]
代碼位置:src/index.js[6]
技巧三:用md去寫組件文檔和示例
十分優雅的文檔和示例書寫方式:文檔和示例統一寫到markdown文件中,在通過編寫md-loader,先轉成html文件,再轉成vue的組件,再渲染,這種做法筆者認爲是太有意思。
先看一下 Element UI 的文檔頁面的框架:
路由組件邏輯(詳細代碼[7]):
// 截取組件文檔的路由代碼片段
const LOAD_DOCS_MAP = {
'zh-CN': path => {
return r => require.ensure([], () =>
r(require(`./docs/zh-CN${path}.md`)),
'zh-CN');
},
'en-US': path => {
return r => require.ensure([], () =>
r(require(`./docs/en-US${path}.md`)),
'en-US');
},
'es': path => {
return r => require.ensure([], () =>
r(require(`./docs/es${path}.md`)),
'es');
},
'fr-FR': path => {
return r => require.ensure([], () =>
r(require(`./docs/fr-FR${path}.md`)),
'fr-FR');
}
};
注意到,路由加載的組件不 vue 組件,而是,一個 markdown 文件。這個過程,是在 webpack 打包過程中自定義一個 loader 來實現:markdown 轉成 vue 來實現的。
詳細實現:build/md-loader/index.js[8]
接下來,將詳細分享文檔如何實現組件演示的效果:
第一步:擴展了markdown的container格式:demo
:::demo ${content}:::
實現代碼:
const md = require('markdown-it')();
const fs = require('fs');
const path = require('path');
const mdContainer = require('markdown-it-container');
module.exports = md => {
md.use(mdContainer, 'demo', {
validate(params) {
return params.trim().match(/^demo\s*(.*)$/);
},
render(tokens, idx) {
const m = tokens[idx].info.trim().match(/^demo\s*(.*)$/);
if (tokens[idx].nesting === 1) {
const description = m && m.length > 1 ? m[1] : '';
const content = tokens[idx + 1].type === 'fence' ? tokens[idx + 1].content : '';
return `<demo-block>
${description ? `<div>${md.render(description)}</div>` : ''}
<!--element-demo: ${content}:element-demo-->
`;
}
return '</demo-block>';
}
});
md.use(mdContainer, 'tip');
md.use(mdContainer, 'warning');
};
const inputPath = path.resolve(__dirname, './alert.md');
const outputPath = path.resolve(__dirname, './alert.html');
const input = fs.readFileSync(inputPath, {encoding: 'utf8'});
const ounput = md.render(input);
fs.writeFileSync(outputPath, ounput, {encoding: 'utf8'});}
執行結果:
提取註釋內容轉成組件的實例實現
第二步:將html轉成ComponentDoc.vue
<template>
<section class="content element-doc">
<h2>Alert 警告</h2>
<p>用於頁面中展示重要的提示信息。</p>
<h3>自定義關閉按鈕</h3>
<p>自定義關閉按鈕爲文字或其他符號。</p>
<!--示例展示 這個步是最關鍵-->
<demo-block>
<template name="source">
<element-demo0 />
</template>
<template name="default"></template>
<slot name="highlight"></slot>
</demo-block>
</section>
</template>
組件:<demo-block>,源碼位置:examples/components/demo-block.vue[9]
DemoBlockComponent效果展示如下圖:
第三步:示例效果展示
-
第一種,組件僅僅只有模板,沒有其他屬性,就跟描述內容插槽一樣,直接以插槽透傳就行; -
第二種,是組件有script內容,怎麼處理呢?如下圖
組件代碼是調用vue-template-compiler模塊生成的,參照:build/md-loader/util.js:L30[10]
技巧四:icon組件示例
Element UI 提供了280個icon,人工搬磚,寫文檔,又得加不少班呀。對於有追求的程序員,當然要有想法了。處理技巧:使用postcss模塊解析icons的樣式文件,提取出el-icon-XXX的className,將所有icon的className組裝成數組中,保存到examples/icon.json[11]
通過樣式class提取icon名字,代碼實現如下:
'use strict';
var postcss = require('postcss');
var fs = require('fs');
var path = require('path');
var fontFile = fs.readFileSync(path.resolve(__dirname, '../../packages/theme-chalk/src/icon.scss'), 'utf8');
// 藉助postcss解析css文件
var nodes = postcss.parse(fontFile).nodes;
var classList = [];
// 通過正則獲取icon的name
nodes.forEach((node) => {
var selector = node.selector || '';
var reg = new RegExp(/\.el-icon-([^:]+):before/);
var arr = selector.match(reg);
if (arr && arr[1]) {
classList.push(arr[1]);
}});
classList.reverse();
// 希望按 css 文件順序倒序排列
console.info(classList.length);
fs.writeFile(
path.resolve(__dirname, '../../examples/icon.json'),
JSON.stringify(classList)
);
技巧三種中是將icons的icons.md生成的ComponentDoc.vue組件,無法編寫代碼來傳入icons數組,那就直接注入 Vue中原型鏈中
// 文檔入口引入
import Vue from 'vue'
import icon from './icon.json';
Vue.prototype.$icon = icon;
icon文檔書寫
圖標集合
<ul class="icon-list">
<!--直接從原型鏈獲取全部icon名字-->
<li v-for="name in $icon" :key="name">
<span>
<i :class="'el-icon-' + name"></i>
<span class="icon-name">{{'el-icon-' + name}}</span>
</span>
</li>
</ul>
效果:element.eleme.io/#/zh-CN/com…[12]
一下子解決這麼多的重複工作😄
技巧五:文檔多語言
文檔多語言,使用腳本生成每中語言,都單獨生成一個vue模板,和技巧二類似,詳細參考:build/bin/i18n.js[13]
參考資料
https://element.eleme.io/: https://link.juejin.cn/?target=https%3A%2F%2Felement.eleme.io%2F
[2]https://github.com/ElemeFE/element: https://link.juejin.cn/?target=https%3A%2F%2Fgithub.com%2FElemeFE%2Felement
[3]https://github.com/ElemeFE/element/blob/45c0ef46f298cc9dfbe72d20039795184a8ddab0/build/bin/new.js: https://link.juejin.cn/?target=https%3A%2F%2Fgithub.com%2FElemeFE%2Felement%2Fblob%2F45c0ef46f298cc9dfbe72d20039795184a8ddab0%2Fbuild%2Fbin%2Fnew.js
[4]https://github.com/ElemeFE/element/blob/45c0ef46f298cc9dfbe72d20039795184a8ddab0/components.json: https://link.juejin.cn/?target=https%3A%2F%2Fgithub.com%2FElemeFE%2Felement%2Fblob%2F45c0ef46f298cc9dfbe72d20039795184a8ddab0%2Fcomponents.json
[5]https://github.com/ElemeFE/element/blob/45c0ef46f298cc9dfbe72d20039795184a8ddab0/build/bin/build-entry.js: https://link.juejin.cn/?target=https%3A%2F%2Fgithub.com%2FElemeFE%2Felement%2Fblob%2F45c0ef46f298cc9dfbe72d20039795184a8ddab0%2Fbuild%2Fbin%2Fbuild-entry.js
[6]https://github.com/ElemeFE/element/blob/45c0ef46f298cc9dfbe72d20039795184a8ddab0/src/index.js: https://link.juejin.cn/?target=https%3A%2F%2Fgithub.com%2FElemeFE%2Felement%2Fblob%2F45c0ef46f298cc9dfbe72d20039795184a8ddab0%2Fsrc%2Findex.js
[7]https://github.com/ElemeFE/element/blob/dev/examples/route.config.js: https://link.juejin.cn/?target=https%3A%2F%2Fgithub.com%2FElemeFE%2Felement%2Fblob%2Fdev%2Fexamples%2Froute.config.js
[8]https://github.com/ElemeFE/element/blob/45c0ef46f298cc9dfbe72d20039795184a8ddab0/build/md-loader/index.js: https://link.juejin.cn/?target=https%3A%2F%2Fgithub.com%2FElemeFE%2Felement%2Fblob%2F45c0ef46f298cc9dfbe72d20039795184a8ddab0%2Fbuild%2Fmd-loader%2Findex.js
[9]https://github.com/ElemeFE/element/blob/45c0ef46f298cc9dfbe72d20039795184a8ddab0/examples/components/demo-block.vue: https://link.juejin.cn/?target=https%3A%2F%2Fgithub.com%2FElemeFE%2Felement%2Fblob%2F45c0ef46f298cc9dfbe72d20039795184a8ddab0%2Fexamples%2Fcomponents%2Fdemo-block.vue
[10]https://github.com/ElemeFE/element/blob/45c0ef46f298cc9dfbe72d20039795184a8ddab0/build/md-loader/util.js#L30: https://link.juejin.cn/?target=https%3A%2F%2Fgithub.com%2FElemeFE%2Felement%2Fblob%2F45c0ef46f298cc9dfbe72d20039795184a8ddab0%2Fbuild%2Fmd-loader%2Futil.js%23L30
[11]https://github.com/ElemeFE/element/blob/45c0ef46f298cc9dfbe72d20039795184a8ddab0/examples/icon.json: https://link.juejin.cn/?target=https%3A%2F%2Fgithub.com%2FElemeFE%2Felement%2Fblob%2F45c0ef46f298cc9dfbe72d20039795184a8ddab0%2Fexamples%2Ficon.json
[12]https://element.eleme.io/#/zh-CN/component/icon#tu-biao-ji-he: https://link.juejin.cn/?target=https%3A%2F%2Felement.eleme.io%2F%23%2Fzh-CN%2Fcomponent%2Ficon%23tu-biao-ji-he
[13]https://github.com/ElemeFE/element/blob/45c0ef46f298cc9dfbe72d20039795184a8ddab0/build/bin/i18n.js: https://link.juejin.cn/?target=https%3A%2F%2Fgithub.com%2FElemeFE%2Felement%2Fblob%2F45c0ef46f298cc9dfbe72d20039795184a8ddab0%2Fbuild%2Fbin%2Fi18n.js
轉自:azuo
https://juejin.cn/post/6966491047257964575
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