webpack配置css单独分离打包

• 项目完成后，执行npm run build，得到bundle.js, index.html和图片
• 此时css，仍是写在bundle.js之中，需要把css单独分离打包

npm i extract-text-webpack-plugin

const path = require('path')
const HTMLPlugin = require('html-webpack-plugin')
const webpack = require('webpack')
const ExtractPlugin = require('extract-text-webpack-plugin')

// 判断是否为dev开发模式
const isDev = process.env.NODE_ENV === 'development'

const config = {
    target: 'web',
    entry: path.join(__dirname, 'src/index.js'),
    output: {
        filename: 'bundle.[hash:8].js',
        path:path.join(__dirname, 'dist')
    },
    module: {
        rules: [
            {
                test: /\.vue$/,
                loader: 'vue-loader'
            },
            {
                test: /\.jsx$/,
                loader: 'babel-loader'
            },
            {
                test: /\.(gif|jpg|jpeg|png|svg)$/,
                use: [
                    {
                        loader: 'url-loader',
                        options: {
                            limit: 1024,
                            name: '[name].[ext]'
                        }
                    }
                ]
            }
        ]
    },
    plugins: [
        new webpack.DefinePlugin({
            'process.env': {
                NODE_ENV: isDev ? '"development"' : '"production"'
            }
        }),
        new HTMLPlugin()
    ]
}

if (isDev) {
    config.module.rules.push({
        test: /\.styl/,
        use: [
            'style-loader',
            'css-loader',
            {
                loader: 'postcss-loader',
                options: {
                    sourceMap: true
                }
            },
            'stylus-loader'
        ]
    })
    config.devtool = '#cheap-module-eval-source-map'
    config.devServer = {
        port: 8000,
        host: '0.0.0.0',
        overlay: {
            errors: true
        },
        hot: true
    },
    config.plugins.push(
        new webpack.HotModuleReplacementPlugin(),
        new webpack.NoEmitOnErrorsPlugin()
    )
} else {
    config.output.filename = '[name].[chunkhash:8].js'
    config.module.rules.push({
        test: /\.styl/,
        use: ExtractPlugin.extract({
            fallback: 'style-loader',
            use: [
                'css-loader',
                {
                    loader: 'postcss-loader',
                    options: {
                        sourceMap: true
                    }
                },
                'stylus-loader'
            ]
        })
    })
    config.plugins.push(
        new ExtractPlugin('styles.[contentHash:8].css')
    )
}

module.exports = config