split chunks for async chunk doesn't work

[lili21]

Do you want to request a feature or report a bug?
bug

What is the current behavior?
there's no async-vendors chunk.

If the current behavior is a bug, please provide the steps to reproduce.

reproduce repo

What is the expected behavior?
async-vendors chunk should be generated.

Please mention other relevant information such as the browser version, Node.js version, webpack version, and Operating System.

Node: v9.3.0
webpack: v4.1.0
OS: macOS 10.13.1

webpack config

module.exports = {
  mode: 'production',
  output: {
    filename: '[name].[chunkhash].js',
    chunkFilename: '[name].[chunkhash].js'
  },
  optimization: {
    splitChunks: {
      cacheGroups: {
        vendors: {
          test: /[\\/]node_modules[\\/]/,
          chunks: 'initial',
          priority: -10,
          name: 'vendors',
        },
        'async-vendors': {
          test: /[\\/]node_modules[\\/]/,
          minChunks: 2,
          chunks: 'async',
          priority: 0,
          name: 'async-vendors'
        }
      }
    },
    runtimeChunk: true,
    namedModules: true,
    namedChunks: true
  }
}

[montogeek]

Thanks for the report!

[lili21]

That was fast. 💯