从零实现Vue的组件库（零）-基本结构以及构建工具

今年三月份入职以来，一直在做后台运营系统，其中重复性工作有很多，其中组件库就是一项。尽管现阶段有很多优秀的开源组件库，但是为了适应产品奇奇怪怪的需求，还是要手动实现一些组件。将其沉淀下来，积累一些自己东西。

概述：首先基于Vue-cli脚手架改装一个组件库的基本构建工具，它具备以下几点功能：

• webpack3.0 升级 webpack4.0 => 更好地完成组件的开发以及打包工作；
• 支持sass => 加速组件样式开发；
• 支持导入markdown以及markdown样式自定义、以及code高亮；
• 自动配置路由。

1. 实例

实例地址：[Fat-Ge UI library](http://fatge.xyz/blog/juejin-example-3#/)

代码地址：[UI-Library code](https://github.com/FatGe/UI-Library)
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2. 安装流程

环境：win-64位、node-v8.12.0

• 安装

  npm install --global vue-cli

  安装vue-cli，之后创建一个ui-library的项目

  vue init webpack ui-library

  创建的项目的package.json中，webpack的版本为3.6.0

  "webpack": "^3.6.0",
  "webpack-bundle-analyzer": "^2.9.0",
  "webpack-dev-server": "^2.9.1",
  "webpack-merge": "^4.1.0"
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  为了升级webpack4.1.2，先把当前webpack以及其相关依赖uninstall

  npm uninstall -D webpack webpack-bundle-analyzer webpack-dev-server webpack-merge
  npm uninstall -D copy-webpack-plugin css-loader eslint-loader file-loader html-webpack-plugin url-loader  friendly-errors-webpack-plugin optimize-css-assets-webpack-plugin uglifyjs-webpack-plugin vue-loader
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  安装webpack4，由于webpack4依赖webpack-cli，所以也需要安装

  npm install -D webpack webpack-cli webpack-bundle-analyzer webpack-dev-server webpack-merge
  npm install -D copy-webpack-plugin css-loader eslint-loader file-loader html-webpack-plugin url-loader  friendly-errors-webpack-plugin optimize-css-assets-webpack-plugin uglifyjs-webpack-plugin vue-loader
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  手动替换 extract-text-webpack-plugin 插件 npm uninstall -D extract-text-webpack-plugin 替换为 npm install -D mini-css-extract-plugin

  安装sass相关依赖 npm install -D node-sass sass-loader --save-dev

• 配置

  • 首先配置webpack的mode，在webpack.dev.conf.js以及webpack.prod.conf.js中分别加上

    const devWebpackConfig = merge(baseWebpackConfig, {
        mode: 'production',
        ...
    })
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    const webpackConfig = merge(baseWebpackConfig, {
        mode: 'development',
        ...
    })
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  • 配置webpack.base.conf.js文件

    // 引入VueLoaderPlugin
    const { VueLoaderPlugin } = require('vue-loader')
    // 添加至
    const devWebpackConfig = merge(baseWebpackConfig, {
        ...
        plugins: [
            new VueLoaderPlugin(),
            ...
        ]
    })
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  • 配置webpack.prod.conf.js文件

    需要删除

    const ExtractTextPlugin = require('extract-text-webpack-plugin')

    const UglifyJsPlugin = require('uglifyjs-webpack-plugin')

    之后配置config项

    const ExtractTextPlugin = require('extract-text-webpack-plugin')
    const { VueLoaderPlugin } = require('vue-loader')
    
    const webpackConfig = merge(baseWebpackConfig, {
        optimization: {
            splitChunks: {
              cacheGroups: {
                vendors: {
                  test: /[\\/]node_modules[\\/]/,
                  chunks: 'initial',
                  name: 'vendors',
                },
                'async-vendors': {
                  test: /[\\/]node_modules[\\/]/,
                  minChunks: 2,
                  chunks: 'async',
                  name: 'async-vendors'
                }
              }
            },
            runtimeChunk: { name: 'runtime' }
        },
        plugins: [
            // 添加VueLoaderPlugin
            new VueLoaderPlugin(),
            ...
            // 引入MiniCssExtractPlugin
            new MiniCssExtractPlugin({
              filename: utils.assetsPath('css/[name].[contenthash:7].css')
            }),
            // Compress extracted CSS. We are using this plugin so that possible
            // duplicated CSS from different components can be deduped.
            new OptimizeCSSPlugin({
              cssProcessorOptions: config.build.productionSourceMap
                ? { safe: true, map: { inline: false } }
                : { safe: true }
            }),
            // see https://github.com/ampedandwired/html-webpack-plugin
            new HtmlWebpackPlugin({
              filename: config.build.index,
              template: 'index.html',
              inject: true,
              minify: {
                removeComments: true,
                collapseWhitespace: true,
                removeAttributeQuotes: true
                // more options:
                // https://github.com/kangax/html-minifier#options-quick-reference
              },
              // necessary to consistently work with multiple chunks via CommonsChunkPlugin
              chunksSortMode: 'dependency'
            }),
            // keep module.id stable when vendor modules does not change
            new webpack.HashedModuleIdsPlugin(),
            // copy custom static assets
            new CopyWebpackPlugin([
              {
                from: path.resolve(__dirname, '../static'),
                to: config.build.assetsSubDirectory,
                ignore: ['.*']
              }
            ])
        ]
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  • 修改utils.js

    exports.cssLoaders = function(options) {
        options = options || {}
    
        // generate loader string to be used with extract text plugin
        function generateLoaders(loader, loaderOptions) {
            let loaders = []
            if (loader) {
                loaders = [{
                    loader: loader + '-loader',
                    options: Object.assign({}, loaderOptions, {
                        sourceMap: options.sourceMap
                    })
                }]
            }
    
            if (options.extract) {
                let extractLoader = {
                    loader: MiniCssExtractPlugin.loader,
                    options: {}
                }
    
                return [extractLoader, 'css-loader'].concat(['postcss-loader'], loaders)
            } else {
    
                return ['vue-style-loader', 'css-loader'].concat(['postcss-loader'], loaders)
            }
        }
    
        return {
            css: generateLoaders(),
            postcss: generateLoaders(),
            less: generateLoaders('less'),
            sass: generateLoaders('sass', { indentedSyntax: true }),
            scss: generateLoaders('sass'),
            stylus: generateLoaders('stylus'),
            styl: generateLoaders('stylus')
        }
    }
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3. 支持导入markdown以及markdown样式自定义

由于 vue-markdown-loader 与vue-loader版本15有兼容性的问题，所以利用 text-loader 将Markdown文档导入并生成String，再编译为markdown文档。

首先 npm install -D text-loader 安装text-loader，用来引入*.md文件，再修改webpack.base.conf.js文件，添加text-loader

rules: [
    ...(config.dev.useEslint ? [createLintingRule()] : []),
    {
        test: /.md$/,
        loader: 'text-loader'
    },
    ...
]
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在引入 marked 对导入的String进行编译

<template>
    <div class="markdown-body" v-html="compiledMarkdown" v-highlight></div>
</template>

import markdown from '../../README.md'
import marked from 'marked'

export default {
  computed: {
    markdowonText () {
      // 编译markdown
      return marked(markdown)
    }
  }
}
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觉得markdown的样式有些丑，可以导入 github-markdown-css

npm install -D github-markdown-css

对样式进行修改。如果markdown中存在着某些code，可以通过 highlight 进行高亮展示

npm install -D highlight

import hljs from 'highlight.js'
// 调整高亮code的样式
import 'highlight.js/styles/vs2015.css'

hljs.configure({ useBR: true })
// 注册一个directive用来添加code高亮
Vue.directive('highlight',function (el) {
    let blocks = el.querySelectorAll('code')

    blocks.forEach(block => {
        hljs.highlightBlock(block)
    })
})
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4. 自动配置路由

利用 require.context 解析某个目录下的文件，将其生成Router的配置

const context = require.context('@/components/', true, /demo\.vue$/)
const componentRouters = context.keys().map(url => {
    const start = url.indexOf('/')
    const end = url.lastIndexOf('/')
    const name = url.substring(start + 1, end)
    const path = `/${name}`
    
    return {
        name,
        path,
        component: require(`@/components${path}/demo`).default
    }
})

export default new Router({
    routes: [
        {
            path: '/',
            name: 'mainPage',
            component: mainPage
        },
        
        ...componentRouters
        ]
    }
)
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