为什么要给 VUE 项目添加 PWA
为什么要添加？因为不管是部署在 IIS，还是 nginx，每次应用部署后，再次访问因为旧的 js 已经不存在，所以页面访问的时候会整个报错，报错的结果就是一个白屏。 为了解决这个问题，我的解决方案是使用 PWA ，这样就可以将 js 缓存到本地，再次发布后，service-worker.js 会使旧的 js 失效，重新请求并缓存 js。
如果对于问题这个有更好的解决方案，务必请大佬指定一二
安装 PWA 的相关依赖包
yarn 安装
代码语言：javascript复制yarn add sw-precache-webpack-plugin --dev
yarn add uglify-es --devnpm 安装
代码语言：javascript复制npm install sw-precache-webpack-plugin --dev-dev
npm install uglify-es --dev-dev添加修改相关配置
下面这些文件忘记出处是哪，Github也能搜到一些，之前写的 PWA 的 Demo 里面拿过来的~
添加 build/service-worker-dev.js
代码语言：javascript复制self.addEventListener('install', () => self.skipWaiting())
self.addEventListener('activate', () => {
self.clients.matchAll({ type: 'window' }).then(windowClients => {
for (let windowClient of windowClients) {
// Force open pages to refresh, so that they have a chance to load the
// fresh navigation response from the local dev server.
windowClient.navigate(windowClient.url)
}
})
})添加 build/service-worker-prod.js
代码语言：javascript复制;(function() {
'use strict'
// Check to make sure service workers are supported in the current browser,
// and that the current page is accessed from a secure origin. Using a
// service worker from an insecure origin will trigger JS console errors.
var isLocalhost = Boolean(
window.location.hostname === 'localhost' ||
// [::1] is the IPv6 localhost address.
window.location.hostname === '[::1]' ||
// 127.0.0.1/8 is considered localhost for IPv4.
window.location.hostname.match(
/^127(?:.(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)){3}$/
)
)
window.addEventListener('load', function() {
if (
'serviceWorker' in navigator &&
(window.location.protocol === 'https:' || isLocalhost)
) {
navigator.serviceWorker
.register('service-worker.js')
.then(function(registration) {
// updatefound is fired if service-worker.js changes.
registration.onupdatefound = function() {
// updatefound is also fired the very first time the SW is installed,
// and there's no need to prompt for a reload at that point.
// So check here to see if the page is already controlled,
// i.e. whether there's an existing service worker.
if (navigator.serviceWorker.controller) {
// The updatefound event implies that registration.installing is set
var installingWorker = registration.installing
installingWorker.onstatechange = function() {
switch (installingWorker.state) {
case 'installed':
// At this point, the old content will have been purged and the
// fresh content will have been added to the cache.
// It's the perfect time to display a "New content is
// available; please refresh." message in the page's interface.
break
case 'redundant':
throw new Error(
'The installing ' 'service worker became redundant.'
)
default:
// Ignore
}
}
}
}
})
.catch(function(e) {
console.error('Error during service worker registration:', e)
})
}
})
})()添加 build/load-minified.js
代码语言：javascript复制'use strict'
const fs = require('fs')
const UglifyJS = require('uglify-es')
module.exports = function(filePath) {
const code = fs.readFileSync(filePath, 'utf-8')
const result = UglifyJS.minify(code)
if (result.error) return ''
return result.code
}修改 build/webpack.prod.conf.js
首先引用sw-precache-webpack-plugin和build/load-minified
const SWPrecacheWebpackPlugin = require('sw-precache-webpack-plugin')
const loadMinified = require('./load-minified')为 webpack 插件 HtmlWebpackPlugin 添加参数 serviceWorkerLoader: `<script>${loadMinified( path.join(__dirname, './service-worker-prod.js'))}</script>
plugins: [
....
new HtmlWebpackPlugin({
filename:
process.env.NODE_ENV === 'testing' ? 'index.html' : 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',
serviceWorkerLoader: `<script>${loadMinified( path.join(__dirname, './service-worker-prod.js'))}</script>`
}),并在最后添加 SWPrecacheWebpackPlugin 插件
代码语言：javascript复制// service worker caching
new SWPrecacheWebpackPlugin({
cacheId: 'ysj-admin',
filename: 'service-worker.js',
staticFileGlobs: ['dist/**/*.{js,html,css}'],
minify: true,
stripPrefix: 'dist/'
})在 /index.html 中注入 service-worker.js
代码语言：javascript复制<%= htmlWebpackPlugin.options.serviceWorkerLoader %>如下所示
代码语言：javascript复制<body>
<div id="app"></div>
<%= htmlWebpackPlugin.options.serviceWorkerLoader %>
<!-- built files will be auto injected -->
</body> 
至此，添加完毕，build 之后查看缓存中是否包含 js 检验结果
注意：PWA 应用需要在本地上运行或者 https 协议下， 要保证你的页面是安全页面。
结语
几分钟就搞定了，然后把之前的一个基于VUE的后台模板项目也升级了，如果有相同需求的可以参考下。
仓库地址：https://github.com/yimogit/me-admin-template 线上预览：https://vue-admin.yimo.link/
