Use extractTextPlugin and postCss plugins in Webpack 2

Question

I am migrating from webpack v1 to v2. I followed the official doc to update webpack.config.js:

...
module: {
    rules: [
        {
            test: /\.css$/,
            use: extractTextPlugin.extract({
                fallback: 'style-loader',
                use: [
                    'css-loader?modules&localIdentName=[path][name]_[local]--[hash:base64:8]',
                    'postcss-loader'
                ],
            }),
            exclude: [...]
        },
        {
            test: /\.css$/,
            use: extractTextPlugin.extract({
                fallback: 'style-loader',
                use: 'css-loader',
            }),
            include: [...]
        }
    ]
},
...
/**
 * postcss: [
 *   nested(),
 *   autoprefixer(),
 *   values
 * ]
 */

My problem is the postcss plugins(nested, autoprefixer, values). Webpack 2 didn't support custom property any more, and suggested use options.

I tried the options and plugins: () => [nested, autoprefixer, values] but can't make it work.

What's the proper way to do this? Thanks.

Answer 1

It is recommended to use a postcss.config.js file which exports an object with the options (see Postcss usage). Your config would look like this (omitting the import statements):

module.exports = {
  plugins: [
    nested(),
    autoprefixer(),
    values
  ]
}

But if you want to, you can specify it directly in the webpack config (as shown in Postcss options):

{
  test: /\.css$/,
  use: extractTextPlugin.extract({
    fallback: 'style-loader',
    use: [
      'css-loader?modules&localIdentName=[path][name]_[local]--[hash:base64:8]',
      {
        loader: 'postcss-loader',
        options: {
          plugins: () => [nested(), autoprefixer(), values]
        }
      }
    ]
  })
  exclude: [...]
},

Note that the options are on the loader itself, not the entire rule.