webpack 代码分离

报错信息
Error: webpack.optimize.CommonsChunkPlugin has been removed, please use config.optimization.splitChunks instead.
原因: webpack 4 版本应该是 废弃了 webpack.optimize.CommonsChunkPlugin, 但是中文网应用了该代码, 导致出错
解决: 在 webpack.common.js 或者 webpack.config.js 添加

// ...
optimization: {
    splitChunks: {
      cacheGroups: {
        commons: {
          name: "commons",
          chunks: "initial",
          minChunks: 2
        }
      }
    }
  }
// ...

注意: optimization 是与 entry 同一级别的