前言：由于项目是基于vue-cli2搭建的，使用的是webpack3.x版本。随着时间的迁移，打包的速度越来越慢，痛下决定将webpack升级到4.0版本。
安装依赖
首先先贴出升级完成后的package.json
"devDependencies": {
"assets-webpack-plugin": "^3.9.10",
"autoprefixer": "^7.1.2",
"babel-core": "^6.22.1",
"babel-helper-vue-jsx-merge-props": "^2.0.3",
"babel-loader": "^7.1.4",
"babel-plugin-syntax-jsx": "^6.18.0",
"babel-plugin-transform-runtime": "^6.22.0",
"babel-plugin-transform-vue-jsx": "^3.7.0",
"babel-preset-env": "^1.3.2",
"babel-preset-stage-2": "^6.22.0",
"chalk": "^2.0.1",
"copy-webpack-plugin": "^5.0.4",
"css-loader": "^3.2.0",
"file-loader": "^4.2.0",
"friendly-errors-webpack-plugin": "^1.7.0",
"html-webpack-plugin": "^3.2.0",
"kity": "^2.0.4",
"less": "^3.0.1",
"less-loader": "^5.0.0",
"mini-css-extract-plugin": "^0.8.0",
"node-notifier": "^5.1.2",
"optimize-css-assets-webpack-plugin": "^5.0.3",
"ora": "^1.2.0",
"portfinder": "^1.0.13",
"postcss-import": "^11.0.0",
"postcss-loader": "^3.0.0",
"postcss-url": "^7.2.1",
"progress-bar-webpack-plugin": "^1.11.0",
"rimraf": "^2.6.0",
"semver": "^5.3.0",
"shelljs": "^0.7.6",
"uglifyjs-webpack-plugin": "^1.1.1",
"url-loader": "^2.1.0",
"vue-loader": "^15.7.1",
"vue-style-loader": "^4.1.2",
"vue-template-compiler": "^2.5.21",
"webpack": "^4.39.3",
"webpack-cli": "^3.3.8",
"webpack-dev-middleware": "^3.7.1",
"webpack-dev-server": "^3.8.0",
"webpack-merge": "^4.2.2",
},
第一步
npm i -D webpack@4.39.0
出现报错：connot find module 'webpack/bin/config-yargs'
报错原因：提示缺少依赖
webpack-cli解决方案：安装依赖
npm i -D webpack-cli@3.3.8
第二步
在安装完webpack-cli之后，在继续npm run dev
出现报错：
var outputName = compilation.mainTemplate.applyPluginsWaterfall('asset-path', outputOptions.filename, {
^
TypeEorror: compilation.mainTemplate.applyPluginsWaterfall is not function
报错原因：
html-webpack-plugin版本过低解决方案：安装依赖
npm i -D html-webpack-plugin@3.2.0
第三步
在升级完html-webpack-plugin之后，在继续npm run dev
出现报错： Module build failed (from ./node_module/vue-loader/index.js):
TypeError: Connot read property 'vue' of undefined.
根据上面描述，很明显是vue-loader的依赖出了问题，想要了解详情的请点击从v14迁移 | vue-loader
报错原因：
vue-loader版本过低解决方案：
安装依赖
npm i -D vue-loader@15.7.1在
webpack.base.conf.js下修改-- const vueLoaderConfig = require('./vue-loader.conf')
-- options: vueLoaderConfig
++ const { VueLoaderPlugin } = require('vue-loader')
++ new VueLoaderPlugin()
具体操作
//const vueLoaderConfig = require('./vue-loader.conf')
const { VueLoaderPlugin } = require('vue-loader')
module.exports = {
...,
module: {
rules: [
{
test: /\.vue$/,
loader: 'vue-loader',
// options: vueLoaderConfig
},
]
},
plugins: [
new VueLoaderPlugin()
]
}
第四步
升级完后继续dev
出现报错：
Module parse failed: Unexpected token
File was process with loaders:
*./node_modules/vue-loaders/lib/index.js
You may need an additional loader to handle the result of these loaders.
.ht-Head-Search{
...
}
这时候会感到困惑，我刚刚升级了
vue-loader到v15版本，怎么还是提示vue-loader的错误，难道是升级的方式不对？继续往下看，发现多了点
css样式的提示，明白了可能是css-loader和vue-style-loader也需要跟着升级报错原因：
css-loader,vue-style-loader版本过低解决方案：安装依赖
npm i -D css-loader@3.2.0 vue-style-loader@4.1.2
第五步
升级是考验耐心的事情，不着急一个坑一个坑的解决，在升级完css-loader和vue-style-loade后，继续dev
出现报错：
Module Warning (from ./node_module/postcss-loader/lib/index):
(Emitted value instead of an instace of Error)
PostCSS Loader
Previous source map found,but options.sourceMap isn't set.
报错原因：
postcss-loader版本过低解决方案：安装依赖
npm i -D postcss-loader@3.0.0
解决development环境下的配置问题
首先在webpack.dev.conf.js 文件下添加mode: 'development',
然后移除NamedModulesPlugin,NoEmitOnErrorsPlugin插件，webpack4已修改为内置插件
module.exports = {
...,
mode: 'development,
...,
plugins: {
//new webpack.NamedModulesPlugin(), // HMR shows correct file names in console on update.
//new webpack.NoEmitOnErrorsPlugin(),
}
}
在这里终于看到了我们熟悉的localhost:8080,说明我们的项目可以成功的在dev环境下运行了，心想升级到webpack4，也是挺简单的嘛，迫不及待的在网页打开地址，想和项目进一步的亲近的时候。却在控制台看见了报错，不说了重新打开编译继续回到正题。
出现报错：
Uncaught TypeError:Connot assign to read only property 'exports' of object '#<Object>'
at Module.eval (BaseClient.js)
at Module../node_module/webpack-dev-srever/client/clients/BaseClient.js
报错原因：说是
es6的import 和es5的module.export不能一起使用，项目全局查询 module.export发现没没有一起使用，排除掉这个可能，真相只有一个，那就是配置出了问题解决方案：
一共有两种解决方案
- 第一种方法 移除
resolve('node_modules/webpack-dev-server/client')
webpack.base.conf.js
module.exports = {
...
module: {
rules: [
{
test: /\.js$/,
loader: 'babel-loader'
// include: [resolve('src'), resolve('test'), resolve('node_modules/webpack-dev-server/client')]
include: [resolve('src'),resolve('test')],
exclude: /node_modules/
},
]
}
}
- 第二种方法 移除
transform-runtime
.babelrc
{
"presets": [
["env", {
"modules": false,
"targets": {
"browsers": ["> 1%", "last 2 versions", "not ie <= 8"]
}
}],
"stage-2"
],
// "plugins": ["transform-vue-jsx", "transform-runtime"]
"plugins": ["transform-vue-jsx"]
}
重新dev,打开控制台没有报错，在这里，终于可以和项目来一波深入亲近了，一波功能乱点确认无可疑报错，开始幻想如何build,生成我们最爱的dist文件
解决production环境下配置问题
第一步
首先在webpack.prod.conf.js文件下，添加mode: 'production'
const webpackConfig = merge(baseWebpackConfig, {
...,
mode: 'production'
})
然后选择build
果然，build的过程没有想象的那么一帆风顺，通过npm run build,
项目还未跑动就被扼杀在摇篮
出现报错：
thorw new RemovedPluginError(errorMessage);
Error: webpack.optimize.CommonsChunkPlugin has been removed, please use config.optimization.splitChunks instead.
报错原因：
webpack4移除了
webpack.optimize.CommonsChunkPlugin解决方案：
在
webpack.prod.conf.js文件下将以下方法删除
- webpack.optimize.CommonsChunkPlugin
- webpack.optimize.CommonsChunkPlugin
- webpack.optimize.CommonsChunkPlugin
- webpack.optimize.ModuleConcatenationPlugin
- OptimizeCSSPlugin
- UglifyJsPlugin
const webpackConfig = merge(baseWebpackConfig, {
...,
plugins: [
//new webpack.optimize.CommonsChunkPlugin(),
//new webpack.optimize.CommonsChunkPlugin({}),
//new webpack.optimize.CommonsChunkPlugin({})，
//new webpack.optimize.ModuleConcatenationPlugin(),
//new OptimizeCSSPlugin({}),
//new UglifyJsPlugin({})
],
})
然后在webpack.prod.conf.js文件下添加以下代码：
const webpackConfig = merge(baseWebpackConfig, {
...,
optimization: {
//取代 new UglifyJsPlugin
minimizer: [
// 压缩代码
new UglifyJsPlugin({
uglifyOptions: {
compress: {
warnings: false,
drop_debugger: true,//关闭debug
drop_console: true,//关闭console
}
},
sourceMap: config.build.productionSourceMap,
parallel: true
}),
// 可自己配置，建议第一次升级先不配置
new OptimizeCSSPlugin({
// cssProcessorOptions: config.build.productionSourceMap
// ? {safe: true, map: {inline: false}, autoprefixer: false}
// : {safe: true}
}),
],
// 识别package.json中的sideEffects以剔除无用的模块，用来做tree-shake
// 依赖于optimization.providedExports和optimization.usedExports
sideEffects: true,
// 取代 new webpack.optimize.ModuleConcatenationPlugin()
concatenateModules: true,
// 取代 new webpack.NoEmitOnErrorsPlugin()，编译错误时不打印输出资源。
noEmitOnErrors: true,
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' }
},
})
第二步
上面操作主要是废除和迁移了一些插件,由于webpack4将其内置，所以无需在plugins下进行实例。
继续build
出现报错：
Error: Chunk.entrypoints: Use Chunks.groupsIterable and filter by instanceof Entrypoint insted
at .../node_module/extract-text-webpack-plugin/dist/index.js
09b24449a1acc0be03_pc.png
报错原因：
extract-text-webpack-plugin:3.0.0并不兼容webpack4解决方案：
官方推荐使用
mini-css-extract-plugin来替换extract-text-webpack-plugin,另一种方法是升级extract-text-webpack-plugin至xtract-text-webpack-plugin@4.0.0-beta.0安装依赖
npm i -D mini-css-extract-plugin@0.8.0安装完成之后，打开
utils.js 和 webpack.prod.conf.js文件
utils.js
// const ExtractTextPlugin = require('extract-text-webpack-plugin')
const MiniCssExtractPlugin = require('mini-css-extract-plugin')
exports.cssLoaders = function (options) {
...
// Extract CSS when that option is specified
// (which is the case during production build)
// if (options.extract) {
// return ExtractTextPlugin.extract({
// use: loaders,
// fallback: 'vue-style-loader',
// publicPath: '../../', //注意: 此处根据路径, 自动更改,添加publicPath，可以在css中使用背景图
// })
// } else {
// return ['vue-style-loader'].concat(loaders)
// }
return [
options.extract ? MiniCssExtractPlugin.loader : 'vue-style-loader',
].concat(loaders)
}
-
webpack.prod.conf.js
添加mini-css-extract-plugin,移除ExtractTextPlugin
//const ExtractTextPlugin = require('extract-text-webpack-plugin')
const MiniCssExtractPlugin = require('mini-css-extract-plugin')
const webpackConfig = merge(baseWebpackConfig, {
...,
plugins: [
new MiniCssExtractPlugin({
filename: utils.assetsPath('css/[name].[contenthash].css'),
allChunks: true,
}),
// new ExtractTextPlugin({
// filename: utils.assetsPath('css/[name].[contenthash].css'),
// Setting the following option to `false` will not extract CSS from codesplit chunks.
// Their CSS will instead be inserted dynamically with style-loader when the codesplit chunk has been loaded by webpack.
// It's currently set to `true` because we are seeing that sourcemaps are included in the codesplit bundle as well when it's `false`,
// increasing file size: https://github.com/vuejs-templates/webpack/issues/1110
// allChunks: true,
// }),
]
})
在build,终于看到可爱的 dist文件了，吃了dev的教训，首先我们还是检查下dist,是否正常的，要是隔壁老王打出了包岂不是一片青青草原。
打开网页，发现所有的背景图全部失效，找到utils.js下的配置看看有什么不对的地方。
发现webpack3中的设置
if (options.extract) {
return ExtractTextPlugin.extract({
use: loaders,
fallback: 'vue-style-loader',
publicPath: '../../', //注意: 此处根据路径, 自动更改,添加publicPath，可以在css中使用背景图
})
} else {
return ['vue-style-loader'].concat(loaders)
}
webpack4中的设置
return [
options.extract ? MiniCssExtractPlugin.loader : 'vue-style-loader',
].concat(loaders)
这明显不对，人家webpack3有配置背景图路径，咱webpack4可不能丢下，修改配置如下即可
return [
options.extract ? {loader:MiniCssExtractPlugin.loader, options: {publicPath: '../../'}} : 'vue-style-loader',
].concat(loaders)
如果有本文章没有出现的报错，请下面留言我会试着帮你解决！！！
如果文章对你有所帮助，请留下你的小爱心
就这样这次webpack3迁移到webpack4的踏坑之旅快走到尾声了，不过这里还有一些bug不一定发生，我简单列出来。
拓展-（可能你的项目还有其他报错）
- 如果你的项目中使用了
web worker,那么你在升级到webpack4运行dev的时候，会出现报错，如下：
Uncaught ReferenceError: window is not defined
其实在worker-loader插件的issues已经有了解决办法，想要了解更多，请戳我
解决办法: 在webpack.base.conf.js文件下加入globalObject: 'this'
module.exports = {
...
output: {
path: config.build.assetsRoot,
filename: '[name].js',
publicPath: process.env.NODE_ENV === 'production'
? config.build.assetsPublicPath
: config.dev.assetsPublicPath,
globalObject: 'this'
}
}
2.如果你的项目出现这个错误
Vue packages version mismatch:
- vue@2.5.21
- vue-template-compiler@2.5.16
This may cause things to work incorrectly. Make sure to use the same version for both.
If you are using vue-loader@>=10.0, simply update vue-template-compiler.
If you are using vue-loader@<10.0 or vueify, re-installing vue-loader/vueify should bump vue-template-compiler to the latest.
@ ./resources/assets/js/app.js 12:13-46
@ multi ./resources/assets/js/app.js ./resources/assets/sass/app.scss
ERROR in ./resources/assets/js/components/steps.vue
Module build failed (from ./node_modules/vue-loader/lib/index.js):
TypeError: Cannot read property 'parseComponent' of undefined
不要担心，这只是你的vue版本和vue-template-compiler不一致导致的，
统一下两个的版本就可以了
- 如果你的项目使用了
eslint报错
TypeError: Cannot read property 'eslint' of undefined
请升级npm i -D eslint-loader@2.2.1
打包优化
一.使用happypack多线程打包
1.安装依赖npm i -D happypack@5.0.1
2.导入插件
webpack.base.conf.js
const HappyPack = require('happypack')
const os = require('os')
// 创建 happypack 共享进程池
const happyThreadPool = HappyPack.ThreadPool({size: os.cpus().length})
module.exports = {
...
module: {
rules: [
...
{
test: /\.js$/,
//loader: 'babel-loader',
use: ['happypack/loader?id=babel'],
// include: [resolve('src'), resolve('test'), resolve('node_modules/webpack-dev-server/client')]
include: [resolve('src'),resolve('test')],
exclude: /node_modules/
}
]
},
plugins: [
new HappyPack({
/*
* 必须配置项
*/
// id 标识符，要和 rules 中指定的 id 对应起来
id: 'babel',
// 需要使用的 loader，用法和 rules 中 Loader 配置一样
// 可以直接是字符串，也可以是对象形式
loaders: ['babel-loader?cacheDirectory'],
// 使用共享进程池中的进程处理任务
threadPool: happyThreadPool,
verbose: true
})
]
}
二.使用DllReferencePlugin打包公共方法
1.新建文件dll.js和 webpack.dll.conf.js,两个文件和webpack.base.conf.js同级。
2.在dll.js文件下添加以下代码
const path = require('path');
const webpack = require('webpack');
const dllConfig = require('./webpack.dll.conf');
const chalk = require('chalk')
const rm = require('rimraf')
const ora = require('ora')
const spinner = ora({
color: 'green',
text: '正为生产环境打包dll包中...'
})
spinner.start()
rm(path.resolve(__dirname, '../dll'), err => {
if (err) throw err
webpack(dllConfig,function (err, stats) {
spinner.stop()
if (err) throw err
process.stdout.write(stats.toString({
colors: true,
modules: false,
children: false,
chunks: false,
chunkModules: false
}) + '\n\n')
console.log(chalk.cyan(' dll打包已完成啦!\n'))
})
});
3.在webpack.dll.conf.js文件下添加以下代码
const path = require('path')
const webpack = require('webpack')
const CleanWebpackPlugin = require('clean-webpack-plugin')
const AssetsPlugin = require('assets-webpack-plugin')
module.exports = {
mode: 'development',
entry: {
vendor: [
'vue/dist/vue.esm.js'
]
},
output: {
path: path.join(__dirname, '../static/js/'), // 生成的文件存放路径
filename: 'dll.[name].[chunkhash].js', // 生成的文件名字(默认为dll.vendor.[hash].js)
library: '[name]_[chunkhash]' // 生成文件的映射关系，与下面DllPlugin中配置对应
},
plugins: [
new CleanWebpackPlugin(['dll','../static/js']),
new webpack.DllPlugin({
// 会生成一个json文件，里面是关于dll.js的一些配置信息
path:path.join(__dirname, '../dll/[name]-manifest.json'),
name: '[name]_[chunkhash]', // 与上面output中配置对应
context: __dirname // 上下文环境路径（必填，为了与DllReferencePlugin存在与同一上下文中）
}),
new AssetsPlugin({ //
filename: 'bundle-conf.json',
path: './dll'
})
]
}
- 安装依赖
npm i -D clean-webpack-plugin@latest assets-webpack-plugin@latest
5.在webpack.prod.conf.js文件下
const AddAssetHtmlPlugin = require('add-asset-html-webpack-plugin')
const CleanWebpackPlugin = require('clean-webpack-plugin')
const boundConf = require('../dll/bundle-conf.json') //bundle-confi.json目录结构要正确
const webpackConfig = merge(baseWebpackConfig, {
...
plugins: [
new CleanWebpackPlugin(['dist']),
new webpack.DllReferencePlugin({
context: __dirname,
manifest: require('../dll/vendor-manifest.json')
}),
//这个主要是将生成的vendor.dll.js文件加上hash值插入到页面中。
new AddAssetHtmlPlugin([{
filepath: path.resolve(`./static/js/${boundConf.vendor.js}`),
outputPath: utils.assetsPath('js'),
publicPath: path.posix.join(config.build.assetsPublicPath, 'static/js'),
includeSourcemap: false,
hash: true,
}]),
]
})
- 在
package.sjon下添加配置"build:dll": "node build/dll.js",
"scripts": {
"dev": "webpack-dev-server --inline --progress --config build/webpack.dev.conf.js",
"start": "npm run dev",
"build": "node build/build.js",
"build:dll": "node build/dll.js"
},
6 只需第一次执行npm run build:dll,打包生成文件之后，以后就不需要在npm run build之前再npm run build:dll了
