vue-element-admin开发模式下style标签热更新失效[解决办法]

参考：https://forum.vuejs.org/t/vue-cli-3-x-style/46306/3

vue.config.js添加配置

 css: {
    sourceMap: false,
    modules: false,
    // 是否使用css分离插件 ExtractTextPlugin
    extract: false
  //   // 开启 CSS source maps?
  //   // sourceMap: false,
  //   // css预设器配置项
  //   // loaderOptions: {},
  //   // 启用 CSS modules for all css / pre-processor files.
  //   // modules: false
  },

 参考：https://github.com/vuejs/vue-cli/issues/2051

vue.config.js添加

   watchOptions: {
      poll: true
    },

参考

vue.config.js添加

    hot: true,
    inline: true,

 最终vue.config.js的配置如下

'use strict'
const path = require('path')
const defaultSettings = require('./src/settings.js')

function resolve(dir) {
  return path.join(__dirname, dir)
}

const name = defaultSettings.title || 'vue Element Admin' // page title
// If your port is set to 80,
// use administrator privileges to execute the command line.
// For example, Mac: sudo npm run
const port = 9527 // dev port

// All configuration item explanations can be find in https://cli.vuejs.org/config/
module.exports = {
  /**
   * You will need to set publicPath if you plan to deploy your site under a sub path,
   * for example GitHub Pages. If you plan to deploy your site to https://foo.github.io/bar/,
   * then publicPath should be set to "/bar/".
   * In most cases please use '/' !!!
   * Detail: https://cli.vuejs.org/config/#publicpath
   */
  publicPath: '/',
  outputDir: 'dist',
  assetsDir: 'static',
  lintOnSave: process.env.NODE_ENV === 'development',
  productionSourceMap: false,
  css: {
    sourceMap: false,
    modules: false,
    // 是否使用css分离插件 ExtractTextPlugin
    extract: false
  //   // 开启 CSS source maps?
  //   // sourceMap: false,
  //   // css预设器配置项
  //   // loaderOptions: {},
  //   // 启用 CSS modules for all css / pre-processor files.
  //   // modules: false
  },
  devServer: {
    port: port,
    open: true,
    hot: true,
    inline: true,
    watchOptions: {
      poll: true
    },
    overlay: {
      warnings: false,
      errors: true
    },
    proxy: {
      // change xxx-api/login => mock/login
      // detail: https://cli.vuejs.org/config/#devserver-proxy
      [process.env.VUE_APP_BASE_API]: {
        target: `http://localhost:${port}/mock`,
        changeOrigin: true,
        pathRewrite: {
          ['^' + process.env.VUE_APP_BASE_API]: ''
        }
      }
    },
    after: require('./mock/mock-server.js')
  },
  configureWebpack: {
    // provide the app's title in webpack's name field, so that
    // it can be accessed in index.html to inject the correct title.
    name: name,
    resolve: {
      alias: {
        '@': resolve('src')
      }
    }
  },
  chainWebpack(config) {
    const cdn = {
      // inject tinymce into index.html
      // why use this cdn, detail see https://github.com/PanJiaChen/tinymce-all-in-one
      js: ['https://cdn.jsdelivr.net/npm/tinymce-all-in-one@4.9.3/tinymce.min.js']
    }
    config.plugin('html')
      .tap(args => {
        args[0].cdn = cdn
        return args
      })
    config.plugins.delete('preload') // TODO: need test
    config.plugins.delete('prefetch') // TODO: need test

    // set svg-sprite-loader
    config.module
      .rule('svg')
      .exclude.add(resolve('src/icons'))
      .end()
    config.module
      .rule('icons')
      .test(/.svg$/)
      .include.add(resolve('src/icons'))
      .end()
      .use('svg-sprite-loader')
      .loader('svg-sprite-loader')
      .options({
        symbolId: 'icon-[name]'
      })
      .end()

    // set preserveWhitespace
    config.module
      .rule('vue')
      .use('vue-loader')
      .loader('vue-loader')
      .tap(options => {
        options.compilerOptions.preserveWhitespace = true
        return options
      })
      .end()

    config
      // https://webpack.js.org/configuration/devtool/#development
      .when(process.env.NODE_ENV === 'development',
        config => config.devtool('cheap-source-map')
      )

    config
      .when(process.env.NODE_ENV !== 'development',
        config => {
          config
            .plugin('ScriptExtHtmlWebpackPlugin')
            .after('html')
            .use('script-ext-html-webpack-plugin', [{
            // `runtime` must same as runtimeChunk name. default is `runtime`
              inline: /runtime..*.js$/
            }])
            .end()
          config
            .optimization.splitChunks({
              chunks: 'all',
              cacheGroups: {
                libs: {
                  name: 'chunk-libs',
                  test: /[\/]node_modules[\/]/,
                  priority: 10,
                  chunks: 'initial' // only package third parties that are initially dependent
                },
                elementUI: {
                  name: 'chunk-elementUI', // split elementUI into a single package
                  priority: 20, // the weight needs to be larger than libs and app or it will be packaged into libs or app
                  test: /[\/]node_modules[\/]_?element-ui(.*)/ // in order to adapt to cnpm
                },
                commons: {
                  name: 'chunk-commons',
                  test: resolve('src/components'), // can customize your rules
                  minChunks: 3, //  minimum common number
                  priority: 5,
                  reuseExistingChunk: true
                }
              }
            })
          config.optimization.runtimeChunk('single')
        }
      )
  }
}

但是重点来了，按照上面的修改完成后，如果修改line.vue如下<style scoped> ...<style>中的样式，比如100%，浏览器还是不能热加载~~~~

但是重点来了，按照上面的修改完成后，如果修改line.vue如下<style scoped> ...<style>中的样式，比如100%，浏览器还是不能热加载~~~~

但是重点来了，按照上面的修改完成后，如果修改line.vue如下<style scoped> ...<style>中的样式，比如100%，浏览器还是不能热加载~~~~

<template>
  <div class="chart-container">
    <chart height="100%" width="100%" />
  </div>
</template>

<script>
import Chart from '@/components/Charts/LineMarker'

export default {
  name: 'LineChart1',
  components: { Chart }
}
</script>

<style scoped>
.chart-container{
  position: relative;
   10%;
  height: calc(100vh - 84px);
}
</style>　　

最终的解决办法，参考https://github.com/vuejs/vue-cli/issues/3480 这个怀疑是版本的问题，但是两个环节的webpack 都是4.29以下的版本，具体是4.28，于是决定版本回退，安装webpack 4.27.1，发现依旧没什么卵用，不能热加载，最后苦逼的对了下配置，发发现是是package.json中的如下版本导致的问题

    "@vue/cli-plugin-babel": "3.5.3",
    "@vue/cli-plugin-eslint": "3.5.1",
    "@vue/cli-plugin-unit-jest": "3.5.3",
    "@vue/cli-service": "3.5.3",　　

正确的版本是，如下

"@vue/cli-plugin-babel": "3.6.0",
"@vue/cli-plugin-eslint": "3.6.0",
"@vue/cli-plugin-unit-jest": "3.6.3",
"@vue/cli-service": "3.6.0",　　

　所以最终的解决方案是：

1.在项目目录执行：npm install webpack@4.27.1 （会修改package.json）

2.修改上述cli-plugin-*的版本问3.6

其他参考

https://github.com/vuejs/vue-cli/issues/3480