webpack.config.js

const path = require('path')
const webpack = require('webpack')
const pkg = require('./package.json')
const ExtractTextPlugin = require('extract-text-webpack-plugin')
const OptimizeCSSPlugin = require('optimize-css-assets-webpack-plugin')

const styleLoader = function(options) {
  var options = options || {}
  var cssLoader = {
    loader: 'css-loader',
    sourceMap: options.sourceMap
  }
  var postcssLoader = {
    loader: 'postcss-loader',
    sourceMap: options.sourceMap
  }

  function generateLoaders (loader, loaderOptions) {
    const loaders = options.usePostCSS ? [cssLoader, postcssLoader] : [cssLoader]

    if (loader) {
      loaders.push({
        loader: loader + '-loader',
        options: Object.assign({}, loaderOptions, {
          sourceMap: options.sourceMap
        })
      })
    }

    // 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'
      })
    } else {
      return ['vue-style-loader'].concat(loaders)
    }
  }

  return {
    css: generateLoaders(),
    less: generateLoaders('less')
  }
}

const isProduction = process.env.NODE_ENV === 'production'

module.exports = {
  entry: './src/main.js',
  output: {
    path: path.resolve(__dirname, './dist'),
    publicPath: 'dist',
    filename: 'index.js',
    library: pkg.name,
    libraryTarget: 'umd',
    umdNamedDefine: true
  },
  module: {
    rules: [
      {
        test: /\.css$/,
        use: [
          'vue-style-loader',
          'css-loader'
        ],
      },      {
        test: /\.vue$/,
        loader: 'vue-loader',
        options: {
          loaders: styleLoader({
            extract: isProduction,
            usePostCSS: isProduction
          })
          // other vue-loader options go here
        }
      },
      {
        test: /\.js$/,
        loader: 'babel-loader',
        exclude: /node_modules/
      },
      {
        test: /\.(png|jpg|gif|svg)$/,
        loader: 'file-loader',
        options: {
          name: '[name].[ext]?[hash]'
        }
      }
    ]
  },
  resolve: {
    alias: {
      'vue$': 'vue/dist/vue.esm.js'
    },
    extensions: ['*', '.js', '.vue', '.json']
  },
  devServer: {
    port: 9000,
    historyApiFallback: true,
    noInfo: true,
    overlay: true
  },
  performance: {
    hints: false
  },
  devtool: '#eval-source-map'
}

if (isProduction) {
  module.exports.devtool = '#source-map'
  // http://vue-loader.vuejs.org/en/workflow/production.html
  module.exports.plugins = (module.exports.plugins || []).concat([
    new webpack.DefinePlugin({
      'process.env': {
        NODE_ENV: '"production"'
      }
    }),
    new webpack.optimize.UglifyJsPlugin({
      sourceMap: true,
      compress: {
        warnings: false
      }
    }),
    new webpack.LoaderOptionsPlugin({
      minimize: true
    }),
    new ExtractTextPlugin({
      publicPath: 'dist',
      filename: 'style.css'
    }),
    new OptimizeCSSPlugin({
      cssProcessorOptions: isProduction
        ? { safe: true, map: { inline: false } }
        : { safe: true }
    })
  ])
}