vue中npm run build打包编译的一系列操作
从package.json 中可以看出，npm run build，其实是执行了 node build/build.js，我们在build文件夹中找到build.js，build主要的工作是：检测node和npm版本，删除dist包，webpack构建打包，在终端输出构建信息并结束，如果报错，则输出报错信息。
'use strict'
require('./check-versions')()
process.env.NODE_ENV = 'production'
const ora = require('ora')// 在终端显示的旋转器插件
const rm = require('rimraf')// 用于删除文件夹
const path = require('path')
const chalk = require('chalk')// 终端文字颜色插件
const webpack = require('webpack')
const config = require('../config')
const webpackConfig = require('./webpack.prod.conf')
const spinner = ora('building for production...')
spinner.start()
// 删除dist文件夹，之后webpack打包
rm(path.join(config.build.assetsRoot, config.build.assetsSubDirectory), err => {
if (err) throw err
webpack(webpackConfig, (err, stats) => {
spinner.stop()
if (err) throw err
process.stdout.write(stats.toString({
colors: true,
modules: false,
children: false, // If you are using ts-loader, setting this to true will make TypeScript errors show up during build.
chunks: false,
chunkModules: false
}) + '\n\n')
if (stats.hasErrors()) {
console.log(chalk.red(' Build failed with errors.\n'))
process.exit(1)
}
console.log(chalk.cyan(' Build complete.\n'))
console.log(chalk.yellow(
' Tip: built files are meant to be served over an HTTP server.\n' +
' Opening index.html over file:// won\'t work.\n'
))
})
})
build.js用到了webpack.prod.conf.js,他与webpack.base.conf.js merge之后，作为webpack配置文件，我们再看看webpack.prod.conf.js,主要做的工作是：
1.提取webpack生成的bundle中的文本，到特定的文件，使得css，js文件与webpack输出的bundle分离。
2.合并基本的webpack配置
3.配置webpack的输出，包括输出路径，文件名格式。
4.配置webpack插件，包括丑化代码。
5.gzip下引入compression插件进行压缩。
'use strict'
const path = require('path')
const utils = require('./utils')
const webpack = require('webpack')
const config = require('../config')
const merge = require('webpack-merge')
const baseWebpackConfig = require('./webpack.base.conf')
const CopyWebpackPlugin = require('copy-webpack-plugin')
const HtmlWebpackPlugin = require('html-webpack-plugin')
// 用于从webpack生成的bundle中提取文本到特定文件中的插件
// 可以抽取出css，js文件将其与webpack输出的bundle分离
const ExtractTextPlugin = require('extract-text-webpack-plugin')
const OptimizeCSSPlugin = require('optimize-css-assets-webpack-plugin')
const UglifyJsPlugin = require('uglifyjs-webpack-plugin')
const env = process.env.NODE_ENV === 'testing'
? require('../config/test.env')
: require('../config/prod.env')
// 合并基础的webpack配置
const webpackConfig = merge(baseWebpackConfig, {
module: {
rules: utils.styleLoaders({
sourceMap: config.build.productionSourceMap,
extract: true,
usePostCSS: true
})
},
devtool: config.build.productionSourceMap ? config.build.devtool : false,
// 配置webpack输出的目录，及文件命名规则
output: {
path: config.build.assetsRoot,
filename: utils.assetsPath("js/[name].[chunkhash].js"),
chunkFilename: utils.assetsPath("js/[id].[chunkhash].js")
},
plugins: [
// webpack插件配置
// http://vuejs.github.io/vue-loader/en/workflow/production.html
new webpack.DefinePlugin({
"process.env": env
}),
// 丑化代码
new UglifyJsPlugin({
uglifyOptions: {
compress: {
warnings: false
}
},
sourceMap: config.build.productionSourceMap,
parallel: true
}),
// // 抽离css文件到单独的文件
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
}),
// Compress extracted CSS. We are using this plugin so that possible
// duplicated CSS from different components can be deduped.
new OptimizeCSSPlugin({
cssProcessorOptions: config.build.productionSourceMap
? { safe: true, map: { inline: false } }
: { safe: true }
}),
// generate dist index.html with correct asset hash for caching.
// you can customize output by editing /index.html
// see https://github.com/ampedandwired/html-webpack-plugin
new HtmlWebpackPlugin({
// 生成并注入index.html
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"
}),
// keep module.id stable when vendor modules does not change
new webpack.HashedModuleIdsPlugin(),
// enable scope hoisting
new webpack.optimize.ModuleConcatenationPlugin(),
// split vendor js into its own file
new webpack.optimize.CommonsChunkPlugin({
name: "vendor",
minChunks(module) {
// any required modules inside node_modules are extracted to vendor
return (
module.resource &&
/\.js$/.test(module.resource) &&
module.resource.indexOf(path.join(__dirname, "../node_modules")) === 0
);
}
}),
// extract webpack runtime and module manifest to its own file in order to
// prevent vendor hash from being updated whenever app bundle is updated
new webpack.optimize.CommonsChunkPlugin({
name: "manifest",
minChunks: Infinity
}),
// This instance extracts shared chunks from code splitted chunks and bundles them
// in a separate chunk, similar to the vendor chunk
// see: https://webpack.js.org/plugins/commons-chunk-plugin/#extra-async-commons-chunk
new webpack.optimize.CommonsChunkPlugin({
name: "app",
async: "vendor-async",
children: true,
minChunks: 3
}),
// copy custom static assets
new CopyWebpackPlugin([
{
from: path.resolve(__dirname, "../static"),
to: config.build.assetsSubDirectory,
ignore: [".*"]
}
])
]
});
// gzip模式下需要引入compression插件进行压缩
if (config.build.productionGzip) {
const CompressionWebpackPlugin = require('compression-webpack-plugin')
webpackConfig.plugins.push(
new CompressionWebpackPlugin({
asset: '[path].gz[query]',
algorithm: 'gzip',
test: new RegExp(
'\\.(' +
config.build.productionGzipExtensions.join('|') +
')$'
),
threshold: 10240,
minRatio: 0.8
})
)
}
if (config.build.bundleAnalyzerReport) {
const BundleAnalyzerPlugin = require('webpack-bundle-analyzer').BundleAnalyzerPlugin
webpackConfig.plugins.push(new BundleAnalyzerPlugin())
}
module.exports = webpackConfig
总结:执行npm run dev或者npm run start，实际是在node环境执行build/dev-server.js, dev-server.js会去拿到config中的端口等配置，通过express起一个服务，通过插件自动打开浏览器，加载webpack编译后放在内存的bundle。
执行npm run build，实际上执行了build/build.js,通过webpack的一系列配置及插件，将文件打包合并丑化，并创建dist目录，放置编译打包后的文件，这将是未来用在生产环境的包。