// 依赖使用 npm 方式引入
import Vue from 'vue'
import 'default-passive-events'
import Cookies from 'js-cookie'

import 'normalize.css/normalize.css' // a modern alternative to CSS resets

import Element from 'element-ui' // vue-element-admin-manage 使用的是 2.13.2 版本，现在升级为 2.15.6版本
import './styles/element-variables.scss'
import '@/styles/index.scss' // global css

import App from './App'
import store from './store'
import router from './router'

import './icons' // icon
import './permission' // permission control
import './utils/error-log' // error log
import * as filters from './filters' // global filters
/**
 * 官方文档：http://www.umyui.com/umycomponent/noticeBefore
 */
import UmyUi from 'umy-ui'
// 引入样式
import 'umy-ui/lib/theme-chalk/index.css'
/**
 * 打印插件 <a href="https://blog.csdn.net/qq_45325810/article/details/124186991" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >参考地址</a>
 */
import Print from 'vue-print-nb'

Vue.use(UmyUi)
Vue.use(Print)
// 这是给ElementUI组件库组件设置默认参数
Vue.use(Element, {
  size: Cookies.get('size') || 'medium', // set element-ui default size
  zIndex: 3000
})

// register global utility filters
Object.keys(filters).forEach(key => {
  Vue.filter(key, filters[key])
})

Vue.config.productionTip = false
const vueMain = new Vue({
  el: '#app',
  router,
  store,
  render: h => h(App)
})
export default vueMain

更改CDN方式引入

在 vue.config 中引入 CDN

文件: vue.config.js

// CDN资源
const cdn = {
  externals: {
    vue: 'Vue',
    'vue-router': 'VueRouter',
    vuex: 'Vuex',
    axios: 'axios',
    'element-ui': 'ELEMENT',
    'umy-ui': 'umy-ui', // umy-ui
    'vue-count-to': 'vue-count-to',
    'vue-i18n': 'vue-i18n',
    'vue-splitpane': 'vue-splitpane',
    'vuedraggable': 'vuedraggable',
    'xlsx': 'xlsx',
    'js-md5': ''
  },
  // externals 资源对应 css cdn地址
  css: [
    'https://cdn.bootcdn.net/ajax/libs/element-ui/2.15.6/theme-chalk/index.min.css',
    'https://cdn.jsdelivr.net/npm/[email protected]/lib/theme-chalk/index.min.css'
  ],
  // externals 资源对应 JS cdn地址
  js: [
    'https://cdn.jsdelivr.net/npm/[email protected]/dist/vue.min.js',
    'https://cdn.jsdelivr.net/npm/[email protected]/dist/vue-router.min.js',
    'https://cdn.jsdelivr.net/npm/[email protected]/dist/vuex.min.js',
    'https://cdn.jsdelivr.net/npm/[email protected]/dist/axios.min.js',
    'https://cdn.bootcdn.net/ajax/libs/element-ui/2.15.6/index.min.js',
    'https://cdn.jsdelivr.net/npm/[email protected]/lib/index.min.js',
    'https://cdn.jsdelivr.net/npm/[email protected]/dist/vue-count-to.min.js',
    'https://cdn.jsdelivr.net/npm/[email protected]/dist/vue-i18n.global.min.js',
    'https://cdn.jsdelivr.net/npm/[email protected]/dist/vue-split-pane.min.js',
    'https://cdn.jsdelivr.net/npm/[email protected]/dist/vuedraggable.umd.min.js',
    'https://cdn.jsdelivr.net/npm/[email protected]/dist/xlsx.full.min.js',
    'https://cdn.jsdelivr.net/npm/[email protected]/build/md5.min.js'
  ]
}

module.exports = {
  publicPath: './',
  outputDir: 'dist',
  assetsDir: 'static',
  lintOnSave: process.env.NODE_ENV === 'development',
  productionSourceMap: false, // 打包成 web页面 使用，一般建议 false，不然会生成很多map文件
  chainWebpack(config) {
    // 引入CDN
    // webpack需要排除的依赖名称和挂载在window上的对象属性名称
    config.set('externals', cdn.externals)
    // 这里的作用是在后面index.html页面中通过link，script标签加载这些cdn链接。
    config.plugin('html').tap(args => {
      args[0].cdn = cdn
      return args
    })
  }
}

index.html 加载 cdn资源

文件: inidex.html, 一般是在 public 文件夹下

<!DOCTYPE html>
<html>

<head>
  <meta charset="utf-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
  <meta name="renderer" content="webkit">
  <meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1">
  <link rel="icon" href="<%= BASE_URL %>favicon.ico">
  <title><%= webpackConfig.name %></title>

   
  <!-- 遍历cdn配置里面加载css文件 -->
  <% for (var i in htmlWebpackPlugin.options.cdn && htmlWebpackPlugin.options.cdn.css) { %>
    <link href="<%= htmlWebpackPlugin.options.cdn.css[i] %>" rel="preload" as="style" />
    <link href="<%= htmlWebpackPlugin.options.cdn.css[i] %>" rel="stylesheet" />
  <% } %>

  <!-- 遍历从cdn配置里面加载js文件 -->
  <% for (var i in htmlWebpackPlugin.options.cdn && htmlWebpackPlugin.options.cdn.js) { %>
    <link href="<%= htmlWebpackPlugin.options.cdn.js[i] %>" rel="preload" as="script" />
  <% } %>
</head>

<body>
  <div id="app"></div>
  <!-- 遍历从cdn配置里面加载js文件 -->
  <% for (var i in htmlWebpackPlugin.options.cdn && htmlWebpackPlugin.options.cdn.js) { %>
    <script src="<%= htmlWebpackPlugin.options.cdn.js[i] %>"></script>
  <% } %>

  <script></script>
</body>

</html>

使用CDN引入资源后的main.js

// 部分 依赖使用 cdn方式引入
import Vue from 'vue'
import 'default-passive-events'
import 'normalize.css/normalize.css' // a modern alternative to CSS resets
import '@/styles/index.scss' // global css

import App from './App'
import store from './store'
import router from './router'

import './icons' // icon
import './permission' // permission control
import './utils/error-log' // error log
import * as filters from './filters' // global filters

/**
 * 打印插件, 没有CDN资源，不使用 CDN引入 <a href="https://blog.csdn.net/qq_45325810/article/details/124186991" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >参考地址</a>
 */
import Print from 'vue-print-nb'
Vue.use(Print)

// register global utility filters
Object.keys(filters).forEach(key => {
  Vue.filter(key, filters[key])
})

Vue.config.productionTip = false
const vueMain = new Vue({
  el: '#app',
  router,
  store,
  render: h => h(App)
})
export default vueMain