vuejs項目性能優化總結
在使用elementUI構建公司管理系統時，發現首屏加載時間長，加載的網絡資源比較多，對系統的體驗性會差一點，並且用webpack打包的vuejs的vendor包會比較大。因此經過蒐集網上全部對於vuejs項目的性能優化，作了有關3方面的優化建議，主要包括：上線代碼包打包、源碼編寫優化、用戶體驗優化。(下面的優化建議只在vue-cli腳手架下作過測試，詳情請參考)php
1.代碼包優化
- 屏蔽sourceMap
- 待下項目開發完成。進行打包源碼上線環節，須要對項目開發環節的開發提示信息以及錯誤信息進行屏蔽，一方面能夠減小上線代碼包的大小；另外一方面提升系統的安全性。在vuejs項目的config目錄下有三個文件dev.env.js(開發環境配置文件)、prod.env.js(上線配置文件)、index.js(通用配置文件)。vue-cli腳手架在上線配置文件會自動設置容許sourceMap打包，因此在上線前能夠屏蔽sourceMap。以下所示，index.js的配置以下,通用配置文件分別對開發環境和上線環境作了打包配置分類，在build對象中的配置信息中，productionSourceMap修改爲false:
'use strict' // Template version: 1.3.1 // see http://vuejs-templates.github.io/webpack for documentation. const path = require('path') module.exports = { dev: { // Paths assetsSubDirectory: 'static', assetsPublicPath: '/', proxyTable: {}, // Various Dev Server settings host: 'localhost', // can be overwritten by process.env.HOST port: 8080, // can be overwritten by process.env.PORT, if port is in use, a free one will be determined autoOpenBrowser: false, errorOverlay: true, notifyOnErrors: true, poll: false, // https://webpack.js.org/configuration/dev-server/#devserver-watchoptions- /** * Source Maps */ // https://webpack.js.org/configuration/devtool/#development devtool: 'cheap-module-eval-source-map', // If you have problems debugging vue-files in devtools, // set this to false - it *may* help // https://vue-loader.vuejs.org/en/options.html#cachebusting cacheBusting: true, cssSourceMap: true }, build: { // Template for index.html index: path.resolve(__dirname, '../dist/ndindex.html'), // Paths assetsRoot: path.resolve(__dirname, '../dist'), assetsSubDirectory: 'static', assetsPublicPath: './', /** * Source Maps */ productionSourceMap: false, // https://webpack.js.org/configuration/devtool/#production devtool: '#source-map', // Gzip off by default as many popular static hosts such as // Surge or Netlify already gzip all static assets for you. // Before setting to `true`, make sure to: // npm install --save-dev compression-webpack-plugin productionGzip: true, productionGzipExtensions: ['js', 'css','svg'], // Run the build command with an extra argument to // View the bundle analyzer report after build finishes: // `npm run build --report` // Set to `true` or `false` to always turn it on or off bundleAnalyzerReport: process.env.npm_config_report } }
- 對項目代碼中的JS/CSS/SVG(*.ico)文件進行gzip壓縮
- 在vue-cli腳手架的配置信息中，有對代碼進行壓縮的配置項，例如index.js的通用配置，productionGzip設置爲true，可是首先須要對compress-webpack-plugin支持，因此須要經過 npm install --save-dev compression-webpack-plugin(若是npm install出錯了，就使用cnpm install安裝。可能網絡比較差npm install會出現頻率比較大)，gzip會對js、css文件進行壓縮處理；對於圖片進行壓縮問題，對於png，jpg，jpeg沒有壓縮效果，對於svg，ico文件以及bmp文件壓縮效果達到50%，在productionGzipExtensions: ['js', 'css','svg']設置須要進行壓縮的什麼格式的文件。對項目文件進行壓縮以後，須要瀏覽器客戶端支持gzip以及後端支持gzip。下面能夠查當作功支持gzip狀態：
'use strict' // Template version: 1.3.1 // see http://vuejs-templates.github.io/webpack for documentation. const path = require('path') module.exports = { build: { // Template for index.html index: path.resolve(__dirname, '../dist/ndindex.html'), // Paths assetsRoot: path.resolve(__dirname, '../dist'), assetsSubDirectory: 'static', assetsPublicPath: './', /** * Source Maps */ productionSourceMap: false, // https://webpack.js.org/configuration/devtool/#production devtool: '#source-map', // Gzip off by default as many popular static hosts such as // Surge or Netlify already gzip all static assets for you. // Before setting to `true`, make sure to: // npm install --save-dev compression-webpack-plugin productionGzip: true, productionGzipExtensions: ['js', 'css','svg'], // Run the build command with an extra argument to // View the bundle analyzer report after build finishes: // `npm run build --report` // Set to `true` or `false` to always turn it on or off bundleAnalyzerReport: process.env.npm_config_report } }
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ResponseHeader- content-encoding:"gzip" - 對路由組件進行懶加載
- 在路由配置文件裏，這裏是router.js裏面引用組件。若是使用同步的方式加載組件，在首屏加載時會對網絡資源加載加載比較多，資源比較大，加載速度比較慢。因此設置路由懶加載，按需加載會加速首屏渲染。在沒有對路由進行懶加載時，在Chrome裏devtool查閱能夠看到首屏網絡資源加載狀況（6requests 3.8MB transfferred Finish:4.67s DOMContentLoaded 2.61s Load 2.70s）。在對路由進行懶加載以後（7requests 800kb transffered Finish2.67s DOMContentLoaded 1.72s Load 800ms）,能夠看見加載速度明顯加快。可是進行懶加載以後，實現按需加載，那麼項目打包不會把全部js打包進app.[hash].js裏面，優勢是能夠減小app.[hash].js體積，缺點就是會把其它js分開打包，形成多個js文件，會有屢次https請求。若是項目比較大，須要注意懶加載的效果。
// 實現懶加載方式 import Vue from "vue"; import Router from "vue-router"; Vue.use(Router); export default new Router({ mode: "history", base: "/facex/district/", routes: [ { path: "/", redirect: "index" }, { path: "/", name: "home", component: resolve=>require(["@/views/home"],resolve), children: [ { // 員工查詢 path: "/employees", component: resolve=>require(["@/components/employees"],resolve) }, { // 首頁 path: "/index", component: resolve=>require(["@/views/index"],resolve) }, { // 訪客查詢 path: "/visitorlist", component: resolve=>require(["@/components/visitorlist"],resolve) }, { path: "/department", component: resolve=>require(["@/views/department"],resolve) }, //識別查詢 { path: "/discriminate", component: resolve=>require(["@/components/discriminate"],resolve) }, { path: "/addDevice", component: resolve=>require(["@/views/addDevice"],resolve) }, { path: "/districtNotice", component: resolve=>require(["@/components/districtNotice"],resolve) } ] }, { path: "/noticeList", name: "noticeList", component: resolve=>require(["@/views/noticeList"],resolve) }, { path: "/login", name: "login", component: resolve=>require(["@/views/login"],resolve) }, { path: "/register", name: "register", component: resolve=>require(["@/views/register"],resolve) }, { path: "/setaccount", name